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authorLeah Rowe <info@minifree.org>2017-04-04 23:28:53 +0000
committerGogs <gogitservice@gmail.com>2017-04-04 23:28:53 +0000
commit2a8d4222cc1a4d2f4ea068da00b7204cde3883d0 (patch)
treea1e6290c5b6e7f09bd43d91718f532b5529d4533 /docs/future
parent60af3bd694ce24e15e38263a6a0ad4e6f313ec78 (diff)
parent15ee46bb2995319f2866089b7cf50f467ab223b7 (diff)
downloadlibrebootfr-2a8d4222cc1a4d2f4ea068da00b7204cde3883d0.tar.gz
librebootfr-2a8d4222cc1a4d2f4ea068da00b7204cde3883d0.zip
Merge branch 'leahleah' of libreboot/libreboot into master
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diff --git a/docs/future/index.md b/docs/future/index.md
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-% Development notes
-
-These are development notes, for future use. For old (obselete) notes,
-see [old.html](old.html).
-
-Or go [back to main task list](../tasks.html).
-
-Table of contents
-=================
-
-- [Standard test](#standard_test)
-- [T60 cpu microcode](#t60_cpu_microcode)
-- [i945 VRAM size](#i945_vram_size)
-- [LCD panels on i945 - fix incompatible
- panels](#lcd_i945_incompatibility)
-
-- [i945 X60/T60 VBT implementation (experimental: testing)](#i945_vbt)
-- [IntelVbtTool results](#intelvbttool_results)
-- [Fallback patches for i945](#fallback_patches)
-
-standard test {#standard_test}
-=============
-
-These logs are usually obtained when testing changes related to graphics
-on i945 (X60 and T60).
-
-- Make a copy of these files:
- - /var/log/dmesg
- - /var/log/kern.log
- - /var/log/Xorg.0.log
- - /proc/ioports
- - /proc/iomem
- - /sys/class/drm/card0/error
-- Record these outputs:
- - sudo intel\_reg\_dumper
- - uname -r
- - lspci -vvvvnnnnxxxx
- - sudo modprobe msr
- - sudo inteltool -a
- - sudo cbmem -c
-- Try some 3D games with latest kernel.
-
-T60 cpu microcode {#t60_cpu_microcode}
-=================
-
-TODO: T60: find (for rare buggy CPUs 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 [t7200q](../t7200q) directory
-(q means quirk).
-
-Every other T7200 tested so far has worked without microcode updates.
-
-i945 VRAM size {#i945_vram_size}
-==============
-
-Apparently, only 8MB VRAM is available on i945 GPUs (though it could do
-64MB):\
-phcoder: No. Hardware default is 8 MiB. When I wanted to make it
-configurable, I saw that docs mention only one other alternative: 1MiB.
-Later isn't event enough for 1024x768 at 24bpp without any acceleration
-or double buffering. It's possible that there are undocumented values.
-Which options do you have in vendor BIOS? How to find out how much vram
-you have:\
-phcoder: TOM - BSM\
-phcoder: check what vendor BIOS offers as options\
-vimuser: I thought it could do 64MB usually\
-phcoder: not accorging to doc.\
-phcoder: see mobile-945-express-chipset-datasheet page 93\
-phcoder: see also
-src/northbridge/intel/i945/{early\_init,northbridge,gma}.c\
-vimuser: "011 = DVMT (UMA) mode, 8 MB of memory pre-allocated for\
-vimuser: frame buffer."\
-vimuser: "Others - reserved"\
-phcoder: the easiest way is a loop at this position which tries
-different values and reads (and prints) BSM with them\
-stefanct: vimuser: they suggest that you change the value and look how
-BSM reacts to that\
-stefanct: as they pointed out earlier vram size = TOM - BSM\
-stefanct: different values of GMS\
-stefanct: phcoder: hm\... this could be a hint. look at the text
-description of TOLUD at page 103\
-stefanct: it mentions 64 MB in the text about BSM as well\
-stefanct: table 18\...\
-phcoder: stefanct: I have a guess which value make is 64 but I will not
-tell to avoid skewing test results\
-stefanct: phcoder: sure\... i assumed you were not sure if it supports
-it at all. testing it properly is of course a good idea :)\
-stefanct: test the various possible (but reserved) values of GMS and see
-what the resulting VRAM size is\
-vimuser: so, TOM - BSM
-
-LCD panels on i945 - fix incompatible panels {#lcd_i945_incompatibility}
-============================================
-
-Fix T60 issues (see incompatible panels listed at
-[../hcl/\#supported\_t60\_list](../hcl/#supported_t60_list)).
-
-Run that tool (resources/utilities/i945gpu/intel-regs.py) as root on
-systems with the offending panels in:
-
-- Coreboot (or libreboot, whatever) with VBIOS (disable native
- graphics also)
-- (Factory BIOS also?)
-
-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).
-
-Other values/registers might also need to be added to the script for
-these tests.
-
-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).
-
-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
-(<http://www.coreboot.org/User:GNUtoo#How_to_get_rid_of_the_vbios_of_the_x60_.5BNew_Version.5D>)
-
-Study how EDID works and how gma.c handles it.
-
-Original getregs.py script can be found at
-<http://hg.mtjm.eu/scripts/file/tip/intel-regs.py> written by Michał
-Masłowski.
-
-About fixing remaining LCD panels on 5345:\
-'polarity' is mentioned in coreboot log (cbmem -c). compare output
-(with working and non-working panel). (and see the other notes in
-docs/future/)
-
-There was a theory that working panels are 6bpc (bits per colour) and
-nonworking are 8bpc, but all EDIDs that we have here are for 6bpc
-panels.
-
-We should compare coreboot logs (from `cbmem -c` from systems with
-working and nonworking panels.
-
-How to dump EDID:
-
- # apt-get install i2c-tools
- # modprobe i2c-dev
-Find out the correct ID to use:
- # i2cdetect -l\
-Example:
-
- # i2cdump -y 2 0x50
-
-Working panel: EDID dump from LG-Philips LP150E05-A2K1:
-
- No size specified (using byte-data access)
- 0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
- 00: XX ff ff ff ff ff ff 00 30 ae 43 40 00 00 00 00 X.......0?C@....
- 10: 00 0f 01 03 80 1e 17 78 ea af 00 99 58 53 8c 2a .??????x??.?XS?*
- 20: 25 50 54 21 08 00 81 80 01 01 01 01 01 01 01 01 %PT!?.??????????
- 30: 01 01 01 01 01 01 30 2a 78 20 51 1a 10 40 30 70 ??????0*x Q??@0p
- 40: 13 00 31 e4 10 00 00 18 28 23 78 20 51 1a 10 40 ?.1??..?(#x Q??@
- 50: 30 70 13 00 31 e4 10 00 00 18 00 00 00 0f 00 90 0p?.1??..?...?.?
- 60: 43 32 90 43 28 14 06 00 32 0c 00 00 00 00 00 fe C2?C(??.2?.....?
- 70: 00 4c 50 31 35 30 45 30 35 2d 41 32 0a 20 00 9b .LP150E05-A2? .?
- 80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- 90: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
-
-Working panel: EDID dump from Boe-Hydis HT14P12-100 FRU: 13N7061
-(Inverter FRU: 41W1010)
-
- 0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
- 00: 00 ff ff ff ff ff ff 00 30 ae 22 40 00 00 00 00 ........0?"@....
- 10: 00 0f 01 03 80 1c 15 78 ea af 40 95 56 4a 8f 25 .??????x??@?VJ?%
- 20: 20 50 54 21 08 00 81 80 01 01 01 01 01 01 01 01 PT!?.??????????
- 30: 01 01 01 01 01 01 30 2a 78 20 51 1a 10 40 30 70 ??????0*x Q??@0p
- 40: 13 00 1d d6 10 00 00 19 25 23 78 20 51 1a 10 40 ?.???..?%#x Q??@
- 50: 30 70 13 00 1d d6 10 00 00 19 00 00 00 0f 00 90 0p?.???..?...?.?
- 60: 43 32 90 43 28 0f 01 00 09 e5 00 00 00 00 00 fe C2?C(??.??.....?
- 70: 00 48 54 31 34 50 31 32 2d 31 30 30 0a 20 00 3f .HT14P12-100? .?
- 80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- 90: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
-
-LTN141XA-L01: revert to libreboot git commit c943281 to see this
-
-**Non-**working panel: EDID dump from Samsung LTN150XG-L08:
-
- 0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
- 00: 00 ff ff ff ff ff ff 00 30 ae 40 40 00 00 00 00 ........0?@@....
- 10: 00 0f 01 03 80 1f 17 78 ea 2d 05 97 57 51 8a 27 .??????x?-??WQ?'
- 20: 23 50 54 21 08 00 01 01 01 01 01 01 01 01 01 01 #PT!?.??????????
- 30: 01 01 01 01 01 01 64 19 00 40 41 00 26 30 18 88 ??????d?.@A.&0??
- 40: 36 00 30 e4 10 00 00 19 28 15 00 40 41 00 26 30 6.0??..?(?.@A.&0
- 50: 18 88 36 00 30 e4 10 00 00 19 00 00 00 0f 00 61 ??6.0??..?...?.a
- 60: 43 32 61 43 28 14 01 00 4c a3 58 47 00 00 00 fe C2aC(??.L?XG...?
- 70: 00 4c 54 4e 31 35 30 58 47 2d 4c 30 38 0a 00 6d .LTN150XG-L08?.m
- 80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- 90: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
- f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
-
-i945 gfx: X60/T60 VBT implementation (experimental: testing) {#i945_vbt}
-============================================================
-
-intel\_bios\_dumper in intel-gpu-tools seems interesting.
-
-**Use 'drm.debug=0x06' kernel parameter when booting in grub!**
-
-Before each test run, boot a live USB and delete the old logs in
-/var/log (kernel log, xorg log, dmesg and so on).
-
-Load (from the ROM) the runningvga.bin for each LCD panel on each
-system; do not execute it, only load it! (coreboot will have to be
-modified). Rename the ROM appropriately, based on the system name and
-the panel name.
-coreboot\_nativegfx\_5868\_plusrunningvga\_t60\_14\_LTD141ECMB.rom, for
-instance. Keep a copy for later use.
-
-You are supposed to:
-
-- enable native graphics in menuconfig
-- include the self-modified VGA ROM (load, but not execute) - for
- reverse engineering the correct VBT tables.
-
-With each boot, make notes about what you see and get logs using the
-[standard test](#standard_test). You will need the files from
-[\#intelvbttool\_results](#intelvbttool_results) for each system.
-
-Results (\# means untested):
-- **X60/X60s:**
- - TMD-Toshiba LTD121ECHB: \#
- - CMO N121X5-L06: \#
- - Samsung LTN121XJ-L07: \#
- - BOE-Hydis HT121X01-101: \#
-- **X60T XGA:**
- - BOE-Hydis HV121X03-100: \#
-- **X60T SXGA+:**
- - BOE-Hydis HV121P01-100: \#
-- **T60 14" XGA:**
- - Samsung LTN141XA-L01: \#
- - CMO N141XC: \#
- - BOE-Hydis HT14X14: \#
- - TMD-Toshiba LTD141ECMB: \#
-- **T60 14" SXGA+**
- - TMD-Toshiba LTD141EN9B: \#
- - Samsung LTN141P4-L02: \#
- - Boe-Hydis HT14P12: \#
-- **T60 15" XGA**
- - Samsung LTN150XG-L08: \#
- - LG-Philips LP150X09: \#
- - 13N7068 (IDtech): \#
- - 13N7069 (CMO): \#
-- **T60 15" SXGA+**
- - LG-Philips LP150E05-A2K1: \#
- - BOE-Hydis HV150P01-100: \#
-- **T60 15" UXGA**
- - BOE-Hydis HV150UX1-100: \#
- - IDTech N150U3-L01: \#
- - BOE-Hydis HV150UX1-102: \#
-- **T50 15" QXGA**
- - IDtech IAQX10N: \#
- - IDtech IAQX10S: \#
-
-[Back to top of page](#pagetop)
-
-intelvbttool test results (VGA ROM dumps) {#intelvbttool_results}
-=========================================
-
-The VBIOS on i945 (intel gpu) platforms is self-modifying; that is, its
-contents change when you run it. intelvbttool takes a dump of the
-currently running vbios, and parses it.
-
-The idea is that we can extract the VBT tables using this knowledge, on
-the X60, X60 Tablet and T60 (Intel GPU).
-
-Here is an example of how VBT was implemented on the ThinkPad X230:
-<http://review.coreboot.org/#/c/5396>.
-
-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).
-
-T60 has DVI on its dock, make sure that the dock is attached when
-getting this output.
-
-Get intelvbttool here: <http://review.coreboot.org/#/c/5842>
-(util/intelvbttool).
-
-Now dump a copy of the running VGA BIOS: **\$ sudo dd if=/dev/mem bs=64k
-of=runningvga.bin skip=12 count=1**\
-Then do (and record the output):
-
- $ ./intelvbttool runningvga.bin > intelvbttool\_out
-
-Backup both files (runningvga.bin and intelvbttool\_out), renaming them
-to match the system and LCD panel used.
-[../misc/\#get\_edid\_panelname](../misc/#get_edid_panelname) will show
-you how to get the name (model) of the LCD panel used.
-
-Test results (\# means untested and all had docks, unless noted).
------------------------------------------------------------------
-
-- **X60/X60s:**
- - TMD-Toshiba LTD121ECHB: \#
- - CMO N121X5-L06: \#
- - Samsung LTN121XJ-L07: \#
- - BOE-Hydis HT121X01-101: \#
-- **X60T XGA (1024x768):**
- - BOE-Hydis HV121X03-100: \#
-- **X60T SXGA+ (1400x1050):**
- - BOE-Hydis HV121P01-100: \#
-- **T60 14" XGA (1024x768):**
- - Samsung LTN141XA-L01: \#
- - CMO N141XC: \#
- - BOE-Hydis HT14X14: \#
- - TMD-Toshiba LTD141ECMB: \#
-- **T60 14" SXGA+ (1400x1050):**
- - TMD-Toshiba LTD141EN9B: \#
- - Samsung LTN141P4-L02: \#
- - Boe-Hydis HT14P12: \#
-- **T60 15" XGA (1024x768):**
- - Samsung LTN150XG-L08: \#
- - LG-Philips LP150X09: \#
- - 13N7068 (IDtech): \#
- - 13N7069 (CMO): \#
-- **T60 15" SXGA+ (1400x1050):**
- - LG-Philips LP150E05-A2K1: \#
- - BOE-Hydis HV150P01-100: \#
-- **T60 15" UXGA (1600x1200):**
- - BOE-Hydis HV150UX1-100: \#
- - IDTech N150U3-L01: \#
- - BOE-Hydis HV150UX1-102: \#
-- **T60 15" QXGA (2048x1536):**
- - IDtech IAQX10N: \#
- - IDtech IAQX10S: \#
-
-Fallback patches {#fallback_patches}
-================
-
-- Todo: test gnutoo's fallback patches:
- <http://www.coreboot.org/Fallback_mechanism> see [this IRC
- log](gnutoo_fallback_patch) (warning, not cleaned up)
-
-Other - unlisted (low priority) {#other}
-===============================
-
-- PTE errors still exist on i945 with 6718 (which is merged).
- <http://review.coreboot.org/#/c/6718/>
- - [dmesg](future/dumps/pte_x60_6718/dmesg)
- - [kern.log](future/dumps/pte_x60_6718/kern.log)
- - This doesn't seem to cause any issues for general use.
-- Implement INT 10H support in i945 native graphics. (this will be a
- lot of work. SeaBIOS has code for some geode boards, to get a
- general idea).
-- T60 15" QXGA (2048x1536): fixed issue where GRUB wouldn't show any
- graphics. (Not many people have this panel)
- - It might be the same issue I ran into with Paul on the X60 (not
- enough memory being allocated) since the same code works on T60
- SXGA+ and UXGA, where GRUB actually display graphics.
-
-Copyright © 2014, 2015 Leah Rowe <info@minifree.org>\
-Permission is granted to copy, distribute and/or modify this document
-under the terms of the Creative Commons Attribution-ShareAlike 4.0
-International license or any later version published by Creative
-Commons; A copy of the license can be found at
-[../cc-by-sa-4.0.txt](../cc-by-sa-4.0.txt)
-
-Updated versions of the license (when available) can be found at
-<https://creativecommons.org/licenses/by-sa/4.0/legalcode>
-
-UNLESS OTHERWISE SEPARATELY UNDERTAKEN BY THE LICENSOR, TO THE EXTENT
-POSSIBLE, THE LICENSOR OFFERS THE LICENSED MATERIAL AS-IS AND
-AS-AVAILABLE, AND MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND
-CONCERNING THE LICENSED MATERIAL, WHETHER EXPRESS, IMPLIED, STATUTORY,
-OR OTHER. THIS INCLUDES, WITHOUT LIMITATION, WARRANTIES OF TITLE,
-MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT,
-ABSENCE OF LATENT OR OTHER DEFECTS, ACCURACY, OR THE PRESENCE OR ABSENCE
-OF ERRORS, WHETHER OR NOT KNOWN OR DISCOVERABLE. WHERE DISCLAIMERS OF
-WARRANTIES ARE NOT ALLOWED IN FULL OR IN PART, THIS DISCLAIMER MAY NOT
-APPLY TO YOU.
-
-TO THE EXTENT POSSIBLE, IN NO EVENT WILL THE LICENSOR BE LIABLE TO YOU
-ON ANY LEGAL THEORY (INCLUDING, WITHOUT LIMITATION, NEGLIGENCE) OR
-OTHERWISE FOR ANY DIRECT, SPECIAL, INDIRECT, INCIDENTAL, CONSEQUENTIAL,
-PUNITIVE, EXEMPLARY, OR OTHER LOSSES, COSTS, EXPENSES, OR DAMAGES
-ARISING OUT OF THIS PUBLIC LICENSE OR USE OF THE LICENSED MATERIAL, EVEN
-IF THE LICENSOR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH LOSSES,
-COSTS, EXPENSES, OR DAMAGES. WHERE A LIMITATION OF LIABILITY IS NOT
-ALLOWED IN FULL OR IN PART, THIS LIMITATION MAY NOT APPLY TO YOU.
-
-The disclaimer of warranties and limitation of liability provided above
-shall be interpreted in a manner that, to the extent possible, most
-closely approximates an absolute disclaimer and waiver of all liability.
-
diff --git a/docs/future/old.md b/docs/future/old.md
deleted file mode 100644
index 8a4453ac..00000000
--- a/docs/future/old.md
+++ /dev/null
@@ -1,253 +0,0 @@
-% Development notes (old/obsolete notes)
-
-For current notes, see [](./).
-
-These are old (obsolete) notes that mare kept because they might become
-useful again in the future.
-
-Table of contents
-=================
-
-- [X60 native graphics initialization (backlight
- controls)](#x60_native_notes)
-
-- [T60 native graphics initialization (backlight
- controls)](#t60_native_notes)
-- [i945: 3D fix (based on 5927) for kernel 3.12+ on
- 5320](#5320_kernel312fix)
-- [i945/x60: coreboot 5927 testing (3D fix for kernel 3.12+ on replay
- code)](#x60_cb5927_testing)
-
-X60 native graphics initialization (with backlight controls) {#x60_native_notes}
-============================================================
-
-**This is now obsolete. A better way was found (included in libreboot):
-<http://review.coreboot.org/#/c/6731/>**
-
-***Also check [\#5320\_kernel312fix](#5320_kernel312fix) (to fix 3D on
-kernel 3.12/higher)***
-
-**The fix below was done on 5320/6 (from review.coreboot.org) but should
-work just fine on later versions of 5320.**
-
-Native gpu init + backlight controls! (Fn keys). Also confirmed on X60
-Tablet (1024x768) and X60 Tablet (1400x1050)
-
-**Add backlight controls:** in *src/mainboard/lenovo/x60/devicetree.cb*,
-change **gpu\_backlight** to **0x879F879E**
-
-That's all! **This has also been backported into libreboot 5th release
-(line 1233 in src/mainboard/lenovo/x60/i915io.c)**. GNUtoo (Denis
-Carikli) told me about the register **BLC\_PWM\_CTL** and that you could
-set it to control backlight. I read that address using devmem2 while
-running the VBIOS:
-
- # devmem2 0xe4361254 w
-
-The change is also included in libreboot 6.
-
-When doing this, it gave back that value. The same trick was used to get
-backlight controls for T60 (see
-[\#t60\_native\_notes](#t60_native_notes)).
-
-Further notes
--------------
-
-Reading **0xe4361254** (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). This person says intel\_backlight has different values
-and uses the register. devmem2 works, needs checking **lspci -vv** for
-where the memory is mapped, which is different than on coreboot; mtjm
-found that it was 0xec061254 on his system (X60 Tablet), and the
-register value is different too. **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.**.
-
-Intel-gpu-tools may prove useful for further debugging:
-<http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/>
-
-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.
-
-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. **Note: this may not be correct; this person
-says that their understanding is based on how the Lenote yeeloong
-works**.
-
-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
-
-phcoder (Vladimir Serbinenko) who is author of 5320
-(review.coreboot.org) talks about 'duty cycle limit' and 'flickering
-frequency'.
-
-[Back to top of page](#pagetop)
-
-T60 native graphics initialization (with backlight controls) {#t60_native_notes}
-============================================================
-
-**This is now obsolete. A better way was found (included in libreboot):
-<http://review.coreboot.org/#/c/6731/>**
-
-***Also check [\#5320\_kernel312fix](#5320_kernel312fix) (to fix 3D on
-kernel 3.12/higher)***
-
-**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**
-
-**Add backlight controls:** in *src/mainboard/lenovo/t60/devicetree.cb*,
-change **gpu\_backlight** to **0x58BF58BE**
-
-Hold on! Check
-[../misc/\#get\_edid\_panelname](../misc/#get_edid_panelname) to know
-what LCD panel you have. This is important for the next step!
-
-Supported panels
-----------------
-
-[../hcl/\#supported\_t60\_list](../hcl/#supported_t60_list).
-
-See [\#lcd\_i945\_incompatibility](./#lcd_i945_incompatibility).
-
-[Back to top of page](#pagetop)
-
-i945: 3D fix (based on 5927) for kernel 3.12+ on 5320 {#5320_kernel312fix}
-=====================================================
-
-**This is now obsolete. Merged in coreboot:
-<http://review.coreboot.org/#/c/5927/>**
-
-**This needs to be rewritten (or better organized, or deleted?)**. This
-is also now included in libreboot 6 (using the proper way, not the
-7c0000 method which was a hack)
-
-**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.**
-
-See [\#x60\_cb5927\_testing](#x60_cb5927_testing) for the original (and
-current) fix, for the replay code. Now we want to implement that on top
-of <http://review.coreboot.org/#/c/5320> which is the current code for
-native graphics initialization on i945.
-
-src/northbridge/intel/i945/gma.c (using the 7c0000 hack) on 5320:
-[5320\_7c0000\_gma.c](dumps/5320_7c0000_gma.c) (rename it to gma.c,
-replacing the current one).
-
-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.
-
-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).
-
-Here is some debugging output using intel\_gpu\_tools v1.2-1 (from
-apt-get repositories) using tool "intel\_gtt":
-
-- kernel 3.14.4:
- - with libreboot 5th release (using the 7c0000 gtt hack from
- 5927/3): <http://paste.debian.net/104306>
- - with coreboot+vgarom: <http://paste.debian.net/104309>
-- kernel 3.2.0-60 (from apt-get repositories):
- - with coreboot (no vbios or native init):
- <http://paste.debian.net/104341>
-
-[Back to top of page](#pagetop)
-
-i945/X60: Coreboot 5927 testing (3D fix for kernel 3.12+ on replay code) {#x60_cb5927_testing}
-========================================================================
-
-**This is now obsolete. Merged in coreboot:
-<http://review.coreboot.org/#/c/5927/>**
-
-**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.**
-
-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).
-
-**The replay code is obsolete (see 5320 changeset on review.coreboot.org
-for better version which supports more systems/screens, and then 5345
-for T60). Information here for reference since that is where the fix was
-first applied.**
-
-Read the information on <http://review.coreboot.org/#/c/5927/>.
-
-For historical purposes, here is a collection of IRC logs that once
-existed on this page, related to the issue:
-[kernel312\_irc](dumps/kernel312_irc).
-
-PGETBL\_CTL differs between VBIOS (-) and native graphics init (+).\
-- PGETBL\_CTL: 0x3ffc0001\
-+ PGETBL\_CTL: 0x3f800001
-
-GTT (graphics translation table) size is PGETBL\_save, max 256 KiB. BSM
-(Base of Stolen Memory) is given by the bios.
-
-- 5927/7: [5927\_7.tar.gz](dumps/5927_7.tar.gz) (GRUB graphics are
- correct now, and 3D still works)
-- 5927/6: [5927\_6.tar.gz](dumps/5927_6.tar.gz) (GRUB graphics still
- corrupt, 3D/everything still works after GRUB)
-- 5927/5: [5927\_5.tar.gz](dumps/5927_5.tar.gz) (GRUB graphics
- corrupt, 3D/everything still works after GRUB)
-- 5927/3: [5927\_3.tar.gz](dumps/5927_3.tar.gz) (3D still works!
- kernel 3.14.4) - the '7c0000' hack
-- 5927/2: [5927\_2.tar.gz](dumps/5927_2.tar.gz) (3D works! kernel
- 3.14.4) - the '7c0000' hack
-- 5927/1 (didn't fix the 3D issue):
- - [cbmem -c](dumps/5927_cbmemc)
- - [/sys/class/drm/card0/error](dumps/5927_crashdump)
- - [.config](dumps/5927_config)
-
-[Back to top of page](#pagetop)
-
-Copyright © 2014, 2015 Leah Rowe <info@minifree.org>\
-Permission is granted to copy, distribute and/or modify this document
-under the terms of the Creative Commons Attribution-ShareAlike 4.0
-International license or any later version published by Creative
-Commons; A copy of the license can be found at
-[../cc-by-sa-4.0.txt](../cc-by-sa-4.0.txt)
-
-Updated versions of the license (when available) can be found at
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