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<!DOCTYPE html>
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<title>libreboot tutorials</title>
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<body>
<header>
<h1 id="pagetop">Development notes</h1>
<aside>These are development notes, for future use.</aside>
</header>
<p>
Or go <a href="../">back to main document index</a>.
</p>
<hr/>
<h2>Contents</h2>
<ul>
<li><a href="#todo">TODO list</a></li>
<li><a href="#standard_test">Standard test</a></li>
<li><a href="#t60_cpu_microcode">T60 cpu microcode</a></li>
<li><a href="#fastboot">Fast boot</a></li>
<li><a href="#lcd_i945_incompatibility">LCD panels on i945 - fix incompatible panels</a></li>
<li><a href="#blind_x60">Blind X60 - kernel git bisect</a></li>
<li><a href="#x60_native_notes">X60 native graphics initialization (backlight controls)</a></li>
<li><a href="#t60_native_notes">T60 native graphics initialization (backlight controls)</a></li>
<li><a href="#5320_kernel312fix">i945: 3D fix (based on 5927) for kernel 3.12+ on 5320</a></li>
<li><a href="#x60_cb5927_testing">i945/x60: coreboot 5927 testing (3D fix for kernel 3.12+ on replay code)</a></li>
<li><a href="#i945_vbt">i945 X60/T60 VBT implementation (experimental: testing)</a></li>
<li><a href="#intelvbttool_results">IntelVbtTool results</a></li>
<li><a href="#cpu_cstates_buzzing">CPU c-states (X60/T60) buzzing sound on CPU idle</a></li>
<li><a href="#battery_eventc">Battery 'event c' on X60 (and T60?)</a></li>
</ul>
<hr/>
<h1 id="todo">TODO (bold means high priority)</h1>
<ul>
<li>
<b><a href="#intelvbttool_results">#intelvbttool_results</a>: Finish getting runningvga.bin dumps and intelvbttool dumps for all known targets on X60 and T60.</b>
<ul>
<li>Figure out why 15" T60 with 1024x768 panel doesn't work on native graphics initialization. And fix it (implementing VBT might, also understanding how
to correctly interpret EDID, according to phcoder and damo22).</li>
<li><b><a href="#i945_vbt">#i945_vbt</a>: Finish getting results when running native init and loading (but not executing) the VBIOS option ROM.</b></li>
<li>When VBT is implemented/tested, also test SeaVGABIOS (part of SeaBIOS)</li>
</ul>
</li>
<li>test that patch (DYNAMIC_CBMEM, <a href="http://review.coreboot.org/#/c/6036">http://review.coreboot.org/#/c/6036</a>) on X60 and T60 for kmalkki</li>
<li>Further study how backlight controls work</li>
<li>funfunctor (from coreboot IRC) wants me to try building libreboot/coreboot on X60 with clang/llvm because he says there are some issues where boards fail when built with this: fchmmr: well you will need to compile the latest clang, here are some instructions: https://gist.github.com/victoredwardocallaghan/38689e88dd7b9a439468 and also: funfunctor: fchmmr: you will need the latest coreboot code and http://review.coreboot.org/#/c/5814/ to get clang to build whatever board. also! <br/><br/>
fchmmr: see this topic http://review.coreboot.org/#/q/status:open+project:coreboot+branch:master+topic:clang-fixes,n,z you will need those fixes to get anywhere with building t60/x60 with clang. at the time of writing that was 6122/1, 6121/1, 6120/1 and 6119/1<br/><br/>
fchmmr: its unclear if http://review.coreboot.org/#/c/6129/ has uncovered a bug yet or not..fchmmr: well this was a bug spotted http://review.coreboot.org/#/c/6052/<br/><br/>
funfunctor says X60 (not sure about T60) ROM's can now be built with Clang/LLVM</li>
<li>Investigate <a href="#battery_eventc">#battery_eventc</a>.</li>
</ul>
<p><a href="#pagetop">Back to top of page</a></p>
<hr/>
<h1 id="standard_test">standard test</h1>
<p>
These logs are usually obtained when testing changes related to graphics on i945 (X60 and T60).
</p>
<ul>
<li>
Make a copy of these files:
<ul>
<li>/var/log/dmesg</li>
<li>/var/log/kern.log</li>
<li>/var/log/Xorg.0.log</li>
<li>/proc/ioports</li>
<li>/proc/iomem</li>
<li>/sys/class/drm/card0/error</li>
</ul>
</li>
<li>
Record these outputs:
<ul>
<li>sudo intel_reg_dumper</li>
<li>uname -r</li>
<li>lspci -vvvvnnnnxxxx</li>
<li>sudo modprobe msr</li>
<li>sudo inteltool -a</li>
<li>sudo cbmem -c</li>
</ul>
</li>
<li>
Try some 3D games with latest kernel.
</li>
</ul>
<p><a href="#pagetop">Back to top of page.</a></p>
<hr/>
<h1 id="t60_cpu_microcode">T60 cpu microcode</h1>
<p>
TODO: T60: find (for rare buggy CPU's that are unstable without microcode updates) if there is a workaround (patched kernel, special parameter, etc) So far, only 1 processor has been found to have issues. See microcode errata sheets http://download.intel.com/design/mobile/SPECUPDT/31407918.pdf and http://download.intel.com/design/mobile/SPECUPDT/30922214.pdf and then look at the debugging results collected in <a href="../t7200q">t7200q</a> directory (q means quirk).
</p>
<p>
Every other T7200 tested so far has worked without microcode updates.
</p>
<p><a href="#pagetop">Back to top of page.</a></p>
<hr/>
<h1 id="fastboot">Fast boot</h1>
<p>
Based on information supplied by Charles Devereaux. Look into this. The following are the files
that he gave me, and what he said:
</p>
<ul>
<li><a href="fastboot/x60.config">x60.config</a></li>
<li><a href="fastboot/get-systemd.sh">get-systemd.sh</a></li>
<li><a href="fastboot/grub.cfg.memdisk">grub.cfg.memdisk</a></li>
<li><a href="fastboot/grub.cfg">grub.cfg</a></li>
</ul>
<p>
failsafes to allow people to experiment with few risks.The memdisk tries to load a grub.cfg from each partition,
failing that from the CBFS, and failing that prepares the serial port and
shows a simple menu reminding the user that this is the memdisk (beeps are
also played) and some simple options (ex: call directly a linux kernel).
</p>
<p>
The grub.cfg from the CBFS tries to load a working grub.cfg from a
thumbdrive, and failing that shows a menu offering to boot on seabios (for
CD boot)
</p>
<p>
This makes it possible to say remove the HD and still have a booting
machine (using a thumbdrive) - which may be an interesting option to offer
to your users (a "rescue/reinstall" thumbdrive, or a simple failsafe in
case the user wants to reinstall from a CD into a brand new HD)
</p>
<p>
It's also hacker friendly:
</p>
<ul>
<li>
the memdisk acts as a failsave in case the flash has had its grub.cfg removed or damanged
</li>
<li>
the flash grub.cfg is a failsafe in case the HD grub.cfg was damaged or removed
</li>
</ul>
<p>
Just some simple if logic, but it does the job.
</p>
<p>
Besides that, if you want to experiment with fast booting, my systemd
configure script follows. Just boot your kernel with
init=/lib/systemd/systemd. You also need to add at the botton of the
resulting /lib/udev/rules.d/99-systemd.rules the following to make network
configuration automatic:<br/>
<b>
SUBSYSTEM=="net", KERNEL!="lo", TAG+="systemd",<br/>
ENV{SYSTEMD_ALIAS}+="/sys/subsystem/net/devices/$name"<br/>
ENV{SYSTEMD_WANTS}="ifup@%k.service"
</b>
</p>
<p>
It will put the systemd stuff in /lib/systemd instead of /usr/lib/systemd
(on debian), allowing a peacefull coexistence, and won't use any of the old
/etc/init.d stuff (major cause of slowdown).
</p>
<p>
This is the exact systemd configuration I used to get a system up in 0.6s
as reported on the mailing list.
</p>
<p>
Further optimizations of the boot-time requires to optimize the kernel
configuration even more. Here is my current .config (everything is
built-in, slowly removing modules (ex: yenta, firewire) one by one to see
where I can gain speed.
</p>
<p><a href="#pagetop">Back to top of page.</a></p>
<hr/>
<h1 id="lcd_i945_incompatibility">LCD panels on i945 - fix incompatible panels</h1>
<p>
Fix T60 issues (see incompatible panels listed at <a href="../index.html#supported_t60_list">../index.html#supported_t60_list</a>).
</p>
<p>
Run that tool (resources/utilities/i945gpu/intel-regs.py) as root on machines with the offending panels in:
</p>
<ul>
<li>Coreboot (or libreboot, whatever) with VBIOS (disable native graphics also)</li>
<li>(Factory BIOS also?)</li>
</ul>
<p>
This shows values in devicetree.cb and src/northbridge/intel/i945/gma.c, the idea is that you run it on factory bios or vbios
and that it will (might) show different values: then you try those in the native graphics (in libreboot).
</p>
<p>
Other values/registers might also need to be added to the script for these tests.
</p>
<p>
check if intel_bios_reader from intel-gpu-tools reports the same value (BIOS has a hardcoded value) for PWM modulation frequency.
This file can read the VBIOS (64K dump).
</p>
<p>
Check other tools in intel-gpu-tools aswell, compare outputs. Possibly add more information to intel-regs.py output (submit changes to mtjm).
Do oprom trace / replay (<a href="http://www.coreboot.org/User:GNUtoo#How_to_get_rid_of_the_vbios_of_the_x60_.5BNew_Version.5D">http://www.coreboot.org/User:GNUtoo#How_to_get_rid_of_the_vbios_of_the_x60_.5BNew_Version.5D</a>)
</p>
<p>
Study how EDID works and how gma.c handles it.
</p>
<p>
Original getregs.py script can be found at <a href="http://hg.mtjm.eu/scripts/file/tip/intel-regs.py">http://hg.mtjm.eu/scripts/file/tip/intel-regs.py</a>
written by Michał Masłowski.
</p>
<p><a href="#pagetop">Back to top of page.</a></p>
<hr/>
<h1 id="blind_x60">Blind X60 - kernel git bisect</h1>
<p>
Older kernels could init GPU on an X60 without a vbios or native graphics.
I have to do a git bisect to find out when that was broken.
</p>
<ul>
<li>See <a href="https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=613979#102">https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=613979#102</a></li>
<li><b>git help bisect</b> has an example of how to bisect</li>
<li>See <a href="http://git-scm.com/book/en/Git-Tools-Debugging-with-Git#Binary-Search">http://git-scm.com/book/en/Git-Tools-Debugging-with-Git#Binary-Search</a></li>
<li>
I have ccache. Read on how to compile kernel using ccache instead of regular gcc. (speeds up compiling). How I installed it:
<ul>
<li>sudo apt-get install ccache</li>
<li>echo 'export PATH="/usr/lib/ccache:$PATH"' | tee -a ~/.bashrc \ && source ~/.bashrc && echo $PATH</li>
</ul>
</li>
</ul>
<p>
Note: "memory_corruption_check=0 i915.lvds_channel_mode=2" kernel parameters were once used
successfully for linux-libre 3.10 on a ThinkPad T60 (distribution: Parabola) to get graphics working.
</p>
<p><a href="#pagetop">Back to top of page</a></p>
<hr/>
<h1 id="x60_native_notes">X60 native graphics initialization (with backlight controls)</h1>
<p>
<b><i>Also check <a href="#5320_kernel312fix">#5320_kernel312fix</a> (to fix 3D on kernel 3.12/higher)</i></b>
</p>
<p>
<b>The fix below was done on 5320/6 (from review.coreboot.org) but should work just fine on later versions of 5320.</b>
</p>
<p>
Native gpu init + backlight controls! (Fn keys). Also confirmed on X60 Tablet (1024x768) and X60 Tablet (1400x1050)
</p>
<p>
<b>Add backlight controls:</b> in <i>src/mainboard/lenovo/x60/devicetree.cb</i>, change <b>gpu_backlight</b> to <b>0x879F879E</b>
</p>
<p>
That's all! <b>This has also been backported into libreboot 5th release (line 1233 in src/mainboard/lenovo/x60/i915io.c)</b>. GNUtoo (Denis Carikli)
told me about the register <b>BLC_PWM_CTL</b> and that you could set it to control backlight. I read that address using devmem2 while running the VBIOS:<br/>
<b># devmem2 0xe4361254 w</b>
</p>
<p>
The change is also included in libreboot 6.
</p>
<p>
When doing this, it gave back that value. The same trick was used to get backlight controls for T60 (see <a href="#t60_native_notes">#t60_native_notes</a>).
</p>
<h2>Further notes</h2>
<p>
Reading <b>0xe4361254</b> (address) in Lenovo BIOS always yields FFFFFFFF, even when writing to it (and writing to it doesn't affect brightness controls).
'mtjm' on IRC found that the buttons (Fn keys) control /sys/class/backlight/acpi_video0 which has no affect on 61254 (BLC_PWM_CTL). He says
intel_backlight has different values and uses the register. devmem2 works, needs checking <b>lspci -vv</b> for where the memory is mapped,
which is different than on coreboot; mtjm found that it was 0xec061254 on his machine (X60 Tablet), and the register value is different too.
<b>This is relevant, because we still don't know how backlight controls are actually handled. We got it working by accident. We need to know more.</b>.
</p>
<p>
Intel-gpu-tools may prove useful for further debugging: <a href="http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/">http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/</a>
</p>
<p>
mtjm says 0xe4300000 is an MMIO region of the gpu (lspci -vv shows it), 0x61254 (BLC_PWM_CTL) is a documented register. Searching the kernel driver for backlight
shows that in intel_panel.c this register is used (there is an XXX comment about finding the right value, where recent kernels get it from.
</p>
<p>
What we want to do is calculate a good value, instead of setting it in devicetree.cb. mtjm says about backlight physics:
it has a light source , uses pulse width modulation (PWM) to turn it on/off, dimming is done by spending less time on.
<b>Note: this may not be correct; he says his understanding is based on how the Lenote yeeloong works</b>.
</p>
<p>
mtjm goes on to say, that the register specifies the frequency used for PWM in its depending on the GPU core frequency, so it
might be possible to calculate it without hardcoded laptop-specific values. Therefore, I am supposed to find out the 'display core frequency'
(mtjm says there might be a register for it; also, it might be in 5320 or the replay code) and the PWM modulation frequency.
https://en.wikipedia.org/wiki/Backlight#Flicker_due_to_backlight_dimming
</p>
<p>
phcoder (Vladimir Serbinenko) who is author of 5320 (review.coreboot.org) talks about 'duty cycle limit' and 'flickering frequency'.
</p>
<p><a href="#pagetop">Back to top of page</a></p>
<hr/>
<h1 id="t60_native_notes">T60 native graphics initialization (with backlight controls)</h1>
<p>
<b><i>Also check <a href="#5320_kernel312fix">#5320_kernel312fix</a> (to fix 3D on kernel 3.12/higher)</i></b>
</p>
<p>
<b>The fix below was done on an earlier version of 5345 changeset (review.coreboot.org), but should work on the current version. it is included in libreboot 6</b>
</p>
<p>
<b>Add backlight controls:</b> in <i>src/mainboard/lenovo/t60/devicetree.cb</i>, change <b>gpu_backlight</b> to <b>0x58BF58BE</b>
</p>
<p>
Hold on! Check <a href="../index.html#get_edid_panelname">../index.html#get_edid_panelname</a> to know what LCD panel you have. This is important for the next step!
</p>
<h2>Supported panels</h2>
<p>
<a href="../index.html#supported_t60_list">../index.html#supported_t60_list</a>.
</p>
<p>
See <a href="#lcd_i945_incompatibility">#lcd_i945_incompatibility</a>.
</p>
<p><a href="#pagetop">Back to top of page</a></p>
<hr/>
<h1 id="5320_kernel312fix">i945: 3D fix (based on 5927) for kernel 3.12+ on 5320</h1>
<p><b>This needs to be rewritten (or better organized, or deleted?)</b>. This is also now included in libreboot 6 (using the proper way, not the 7c0000 method which was a hack)</p>
<p>
<b>This was done on 5320/6 so far. The fix below is for 5320/6 which is now obsolete. This needs to be re-done for the latest version
of 5320. The fix below is (in practise) only for reference, therefore.</b>
</p>
<p>
See <a href="#x60_cb5927_testing">#x60_cb5927_testing</a> for the original (and current) fix, for the replay code. Now we want
to implement that on top of <a href="http://review.coreboot.org/#/c/5320">http://review.coreboot.org/#/c/5320</a>
which is the current code for native graphics initialization on i945.
</p>
<p>
src/northbridge/intel/i945/gma.c (using the 7c0000 hack) on 5320: <a href="dumps/5320_7c0000_gma.c">5320_7c0000_gma.c</a> (rename it to gma.c,
replacing the current one).
</p>
<p>
The above is a hack (as is the original). A better (more correct) method is implemented in later versions of 5927, so
that should also be adapted for 5320. For now, you can use the above fix.
</p>
<p>
The correct way to do it is to set gtt address to (end of stolen memory - gtt size), which is what later versions of 5927 do (successfully).
</p>
<p>
Here is some debugging output using intel_gpu_tools v1.2-1 (from trisquel repositories) using tool "intel_gtt":
</p>
<ul>
<li>
Trisquel 6. kernel 3.14.4:
<ul>
<li>with libreboot 5th release (using the 7c0000 gtt hack from 5927/3): <a href="http://paste.debian.net/104306">http://paste.debian.net/104306</a></li>
<li>with coreboot+vgarom: <a href="http://paste.debian.net/104309">http://paste.debian.net/104309</a></li>
</ul>
</li>
<li>
Trisquel 6. kernel 3.2.0-60 (from Trisquel repositories):
<ul>
<li>with coreboot (no vbios or native init): <a href="http://paste.debian.net/104341">http://paste.debian.net/104341</a></li>
</ul>
</li>
</ul>
<p><a href="#pagetop">Back to top of page</a></p>
<hr/>
<h1 id="x60_cb5927_testing">i945/X60: Coreboot 5927 testing (3D fix for kernel 3.12+ on replay code)</h1>
<p><b>The latest version as-is (5927/11) has not been tested by me yet. Always boot with 'drm.debug=0x06' kernel parameter when testing this.</b></p>
<p>
This is the fix for 3D on kernel 3.12 and higher on i945 (ThinkPad X60 in this case). This is for the replay code.
Libreboot 5th release has a version of this backported already (based on 5927/3 using the '7c0000' hack).
</p>
<p>
<b>
The replay code is obsolete (see 5320 changeset on review.coreboot.org for better version
which supports more machines/screens, and then 5345 for T60). Information here for reference since that is where the fix was first applied.
</b>
</p>
<p>
Read the information on <a href="http://review.coreboot.org/#/c/5927/">http://review.coreboot.org/#/c/5927/</a>.
</p>
<p>
For historical purposes, here is a collection of IRC logs that once existed on this page, related to the issue:
<a href="dumps/kernel312_irc">kernel312_irc</a>.
</p>
<p>
PGETBL_CTL differs between VBIOS (-) and native graphics init (+).<br/>
- PGETBL_CTL: 0x3ffc0001<br/>
+ PGETBL_CTL: 0x3f800001
</p>
<p>GTT (graphics translation table) size is PGETBL_save, max 256 KiB. BSM (Base of Stolen Memory) is given by the bios.</p>
<ul>
<li>5927/7: <a href="dumps/5927_7.tar.gz">5927_7.tar.gz</a> (GRUB graphics are correct now, and 3D still works)</li>
<li>5927/6: <a href="dumps/5927_6.tar.gz">5927_6.tar.gz</a> (GRUB graphics still corrupt, 3D/everything still works after GRUB)</li>
<li>5927/5: <a href="dumps/5927_5.tar.gz">5927_5.tar.gz</a> (GRUB graphics corrupt, 3D/everything still works after GRUB)</li>
<li>5927/3: <a href="dumps/5927_3.tar.gz">5927_3.tar.gz</a> (3D still works! kernel 3.14.4) - the '7c0000' hack</li>
<li>5927/2: <a href="dumps/5927_2.tar.gz">5927_2.tar.gz</a> (3D works! kernel 3.14.4) - the '7c0000' hack</li>
<li>
5927/1 (didn't fix the 3D issue):
<ul>
<li><a href="dumps/5927_cbmemc">cbmem -c</a></li>
<li><a href="dumps/5927_crashdump">/sys/class/drm/card0/error</a></li>
<li><a href="dumps/5927_config">.config</a></li>
</ul>
</li>
</ul>
<p><a href="#pagetop">Back to top of page</a></p>
<hr/>
<h1 id="i945_vbt">i945 gfx: X60/T60 VBT implementation (experimental: testing)</h1>
<p>
intel_bios_dumper (use man) in intel-gpu-tools seems interesting.
</p>
<p>
<b>Use 'drm.debug=0x06' kernel parameter when booting in grub! Make sure to use kernel 3.14.4 as before (or any recent kernel).</b>
</p>
<p>
Before each test run, boot a live USB and delete the old logs in /var/log (kernel log, xorg log, dmesg and so on).
</p>
<p>
Use latest 5927/5320/5345 on X60/T60 (with GTT/3D/kernel3.12 fix) with native graphics initialization.
Load (from the ROM) the runningvga.bin for each LCD panel on each machine; do not execute it, only load it!
Rename the ROM appropriately, based on the machine name and the panel name. coreboot_nativegfx_5868_plusrunningvga_t60_14_LTD141ECMB.rom,
for instance. Keep a copy for later use.
</p>
<p>It is (theoretically) supposed to:</p>
<ul>
<li>Enable kernel to see VBT tables so that it can see the panel. (theoretically this will make T60 15" XGA/1024x768 work)</li>
</ul>
<p>You are supposed to:</p>
<ul>
<li>enable native graphics in menuconfig</li>
<li>include the self-modified VGA ROM (load, but not execute) - for reverse engineering the correct VBT tables.</li>
</ul>
<p>
With each boot, make notes about what you see and get logs using the <a href="#standard_test">standard test</a>.
You will need the files from <a href="#intelvbttool_results">#intelvbttool_results</a> for each machine.
</p>
Results (# means untested):
<ul>
<li>
<b>X60/X60s:</b>
<ul>
<li>TMD-Toshiba LTD121ECHB: #</li>
<li>CMO N121X5-L06: #</li>
<li>Samsung LTN121XJ-L07: #</li>
<li>BOE-Hydis HT121X01-101: #</li>
</ul>
</li>
<li>
<b>X60T XGA:</b>
<ul>
<li>BOE-Hydis HV121X03-100: #</li>
</ul>
</li>
<li>
<b>X60T SXGA+:</b>
<ul>
<li>BOE-Hydis HV121P01-100: #</li>
</ul>
</li>
<li>
<b>T60 14" XGA:</b>
<ul>
<li>Samsung LTN141XA-L01: #</li>
<li>CMO N141XC: #</li>
<li>BOE-Hydis HT14X14: #</li>
<li>TMD-Toshiba LTD141ECMB: #</li>
</ul>
</li>
<li>
<b>T60 14" SXGA+</b>
<ul>
<li>TMD-Toshiba LTD141EN9B: #</li>
<li>Samsung LTN141P4-L02: #</li>
<li>Boe-Hydis HT14P12: #</li>
</ul>
</li>
<li>
<b>T60 15" XGA</b>
<ul>
<li>Samsung LTN150XG-L08: #</li>
<li>LG-Philips LP150X09: #</li>
<li>13N7068 (IDtech): #</li>
<li>13N7069 (CMO): #</li>
</ul>
</li>
<li>
<b>T60 15" SXGA+</b>
<ul>
<li>LG-Philips LP150E05-A2K1: #</li>
<li>BOE-Hydis HV150P01-100: #</li>
</ul>
</li>
<li>
<b>T60 15" UXGA</b>
<ul>
<li>BOE-Hydis HV150UX1-100: #</li>
<li>IDTech N150U3-L01: #</li>
<li>BOE-Hydis HV150UX1-102: #</li>
</ul>
</li>
<li>
<b>T50 15" QXGA</b>
<ul>
<li>IDtech IAQX10N: #</li>
<li>IDtech IAQX10S: #</li>
</ul>
</li>
</ul>
<p><a href="#pagetop">Back to top of page</a></p>
<hr/>
<h1 id="intelvbttool_results">intelvbttool test results (VGA ROM's)</h1>
<p>
The VBIOS on i945 (intel gpu) platforms is self-modifying; that is,
it's contents change when you run it. intelvbttool takes a dump of
the currently running vbios, and parses it.
</p>
<p>
The idea is that we can extract the VBT tables using this knowledge, on the X60, X60 Tablet and T60 (Intel GPU).
</p>
<p>
Here is an example of how VBT was implemented on the ThinkPad X230:
<a href="http://review.coreboot.org/#/c/5396" target="_blank">http://review.coreboot.org/#/c/5396</a>.
</p>
<p>
Use this kernel:
<a href="http://samnoble.org/thinkpad/kernel/linux-image-3.14.4-gnuowen_2_i386.deb">http://samnoble.org/thinkpad/kernel/linux-image-3.14.4-gnuowen_2_i386.deb</a>
</p>
<p>
You'll need to build a T60 ROM with SeaBIOS and the VGA ROM (for Intel GPU). An X60 ROM is also needed (same configuration, using the VGA ROM for X60).
</p>
<p>
T60 has DVI on it's dock, make sure that the dock is attached when getting this output.
</p>
<p>
Get intelvbttool here: <a href="http://review.coreboot.org/#/c/5842">http://review.coreboot.org/#/c/5842</a> (util/intelvbttool).
</p>
<p>
Now dump a copy of the running VGA BIOS:
<b>$ sudo dd if=/dev/mem bs=64k of=runningvga.bin skip=12 count=1</b><br/>
Then do (and record the output):<br/>
<b>$ ./intelvbttool runningvga.bin > intelvbttool_out</b>
</p>
<p>
Backup both files (runningvga.bin and intelvbttool_out), renaming them to match the machine and LCD panel used.
<a href="../index.html#get_edid_panelname">../index.html#get_edid_panelname</a> will show you how to get the name (model) of the LCD panel used.
</p>
<h2>Test results (# means untested and all had docks, unless noted).</h2>
<ul>
<li>
<b>X60/X60s:</b>
<ul>
<li>TMD-Toshiba LTD121ECHB: #</li>
<li>CMO N121X5-L06: #</li>
<li>Samsung LTN121XJ-L07: #</li>
<li>BOE-Hydis HT121X01-101: #</li>
</ul>
</li>
<li>
<b>X60T XGA (1024x768):</b>
<ul>
<li>BOE-Hydis HV121X03-100: #</li>
</ul>
</li>
<li>
<b>X60T SXGA+ (1400x1050):</b>
<ul>
<li>BOE-Hydis HV121P01-100: #</li>
</ul>
</li>
<li>
<b>T60 14" XGA (1024x768):</b>
<ul>
<li>Samsung LTN141XA-L01: #</li>
<li>CMO N141XC: #</li>
<li>BOE-Hydis HT14X14: #</li>
<li>TMD-Toshiba LTD141ECMB: #</li>
</ul>
</li>
<li>
<b>T60 14" SXGA+ (1400x1050):</b>
<ul>
<li>TMD-Toshiba LTD141EN9B: #</li>
<li>Samsung LTN141P4-L02: #</li>
<li>Boe-Hydis HT14P12: #</li>
</ul>
</li>
<li>
<b>T60 15" XGA (1024x768):</b>
<ul>
<li>Samsung LTN150XG-L08: #</li>
<li>LG-Philips LP150X09: #</li>
<li>13N7068 (IDtech): #</li>
<li>13N7069 (CMO): #</li>
</ul>
</li>
<li>
<b>T60 15" SXGA+ (1400x1050):</b>
<ul>
<li>LG-Philips LP150E05-A2K1: #</li>
<li>BOE-Hydis HV150P01-100: #</li>
</ul>
</li>
<li>
<b>T60 15" UXGA (1600x1200):</b>
<ul>
<li>BOE-Hydis HV150UX1-100: #</li>
<li>IDTech N150U3-L01: #</li>
<li>BOE-Hydis HV150UX1-102: #</li>
</ul>
</li>
<li>
<b>T60 15" QXGA (2048x1536):</b>
<ul>
<li>IDtech IAQX10N: #</li>
<li>IDtech IAQX10S: #</li>
</ul>
</li>
</ul>
<p><a href="#pagetop">Back to top of page.</a></p>
<hr/>
<h1 id="cpu_cstates_buzzing">Buzzing / static noise when not using idle=halt or processor.max_cstate=2 in GRUB</h1>
<p>
When idle, the X60 and T60 make a high pitched whining sound. With a recorder, find out where it originates from.
'processor.max_cstate=2' or 'idle=halt' kernel parameters can be used in GRUB to remove it.
Alternatively (and for better battery life), another method is to use 'powertop' (see docs/index.html in libreboot release
archives).
</p>
<p>
funfunctor in IRC says: <i>"sounds like the gain is set to high, AGC of a ADC is not setup correctl probably"</i>.
</p>
<p>
damo22 in IRC says: <i>"damo22: it seems like the T60 (happens on X60 aswell) does not
support certain cpu C-states but is being forced to use them and this causes a noise. i believe it's because
it doesnt let the cpu go into low power state."</i>.
</p>
<p>
CareBear\ in IRC says: <i>"it has to do with the CPU and chipset switching power states differently with coreboot than with the factory BIOS and as a result the power supply circuitry on the mainboard emits that noise. the whine is quite clearly directly related to the CPU switching between power states
"</i>
</p>
<p>
Another comment (mailing list):<br/>
If this noise doesn't occur with
the vendor firmware, has anybody checked if coreboot uses the same
power management timing settings? (e.g. C4-TIMING_CNT, see [1], there
might be more such settings not mentioned in the public datasheet) <br/>
<b>[1] Intel I/O Controller Hub 7 (ICH7) Family Datasheet Document Number: 307013-003 </b>
</p>
<p>
</p>
<p><a href="#pagetop">Back to top of page.</a></p>
<hr/>
<h1 id="battery_eventc">Battery 'event c' on X60 (and T60?)</h1>
<p>
Look into this later. This isn't necessarily a bug, just a part of the code which someone noticed that seems odd.
</p>
<p>
funfuctor: fchmmr: what is 'eventc' exactly in the devicetree of your board? Is that meant to be programed sequentially somehow?<br/>
fchmmr: looks like something with EC<br/>
fchmmr: src/ec/lenovo/h8/chip.h: u8 eventc_enable;<br/>
fchmmr: src/ec/lenovo/h8/h8.c: ec_write(0x1c, conf->eventc_enable);<br/>
funfuctor: fchmmr: yes, better ask phcoder-screen why eventc is defined twice<br/>
funfuctor: and which value is correct<br/>
fchmmr: looks like 0x3c is incorrect<br/>
fchmmr: just a guess<br/>
fchmmr: in devicetree.cb it goes event2 then 3 4 5 6 7 c 8 9 then a b c d<br/>
fchmmr: but i don't know what 'event c' is<br/>
funfuctor: fchmmr: interesting, well in that case you could prob figure it out yourself..<br/>
funfuctor: fchmmr: the order should not matter. basically devicetree is syntax for fill in a C struct<br/>
funfuctor: fchmmr: look closely at build/mainboard/lenovo/t60/static.c<br/>
fchmmr: funfunctor: it was sven schnelle who wrote that (I used 'git blame')<br/>
fchmmr: I think "eventc" has something to do with battery<br/>
fchmmr: commit 95ebe66f7f5fef64d363cb48e5a441ad505353d1<br/>
fchmmr: Author: Sven Schnelle <svens@stackframe.org><br/>
fchmmr: Date: Thu Apr 28 09:29:06 2011 +0000<br/>
fchmmr: that's the commit that added those lines.<br/>
fchmmr: funfunctor:<br/>
fchmmr: "" // C: OEM information<br/>
fchmmr: src/ec/lenovo/h8/acpi/battery.asl<br/>
funfuctor: fchmmr: i'll leave you with the issue of fixing the devicetree duplicate value<br/>
funfuctor: fchmmr: you need to read the datasheet to figure out what register 0x3C is<br/>
funfuctor: sorry *0x1C rather<br/>
funfuctor: grep eventc src/ec/lenovo/h8/h8.c<br/>
funfuctor: ec_write(0x1c, conf->eventc_enable);<br/>
Also look in src/ec/lenovo/h8/h8.c and src/ec/lenovo/h8/chip.h and src/mainboard/lenovo/x60/devicetree.cb<br/>
Do a 'git blame' and a 'git log path/to/file' etc. ask sven, even.
</p>
<p><a href="#pagetop">Back to top of page.</a></p>
<hr/>
<h1 id="unlisted">Unlisted Notes</h1>
<p>
funfunctor: shadow compiling means you run both compilers (context: GCC and Clang/LLVM) at the same time. If one compiler misses a problem the other compiler hopefully finds it<br/>
funfunctor: fchmmr: blow your mind (compiler security and reprodicible builds) - http://scienceblogs.com/goodmath/2007/04/15/strange-loops-dennis-ritchie-a/
</p>
<p>
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</p>
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Copyright © 2014 Francis Rowe, All Rights Reserved.<br/>
See <a href="../license.html">../license.html</a> for license conditions.
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