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authorFrancis Rowe <info@gluglug.org.uk>2015-10-19 03:21:08 +0100
committerFrancis Rowe <info@gluglug.org.uk>2015-10-19 03:21:08 +0100
commitfecd062121e47bc1ffaa926b3be56e43946129c8 (patch)
tree773755eebb2984a5dc29f89a9bf34a334a2480f7 /docs
parent0f32e478e9f0014ab36e57b94407f686d11575f5 (diff)
downloadlibrebootfr-fecd062121e47bc1ffaa926b3be56e43946129c8.tar.gz
librebootfr-fecd062121e47bc1ffaa926b3be56e43946129c8.zip
docs/hcl/gm45_lcd.html: Notes about LVDS dual/single auto-detect
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-rw-r--r--docs/hcl/gm45_lcd.html18
1 files changed, 4 insertions, 14 deletions
diff --git a/docs/hcl/gm45_lcd.html b/docs/hcl/gm45_lcd.html
index 137bc686..0b25ab45 100644
--- a/docs/hcl/gm45_lcd.html
+++ b/docs/hcl/gm45_lcd.html
@@ -44,25 +44,15 @@
Current workaround:
</h1>
<p>
- T500/R400 are clones of the T400. See <b>coreboot/src/mainboard/lenovo/t400/devicetree.cb</b> in libreboot,
- and note that <b>register "gfx.lvds_dual_channel" = "0"</b> - in other words, single channel LVDS mode is
- enforced. This works on the lower resolution panels (1280x800), but not on the higher ones.
- </p>
- <p>
- For the high-res panels, re-compiling with <b>register "gfx.lvds_dual_channel" = "1"</b> partially solves
- the problem for those displays; there is still no display in GRUB, but once the kernel takes over, there
- is a display.
- </p>
- <p>
- Linux (kernel) has its own init code (including EDID parsing). The current suspicion is that coreboot's
- own initialization code has buggy EDID parsing in some way, such that the proper settings for the panel
- are not used, leading to the failure. The actual graphics initialization does work.
+ Libreboot (git, and releases after 20150518) now automatically detect whether
+ to use single or dual link LVDS configuration. If you're using an older version,
+ use the instructions below.
</p>
<p>
The i915 module in the Linux kernel also provides an option to set the LVDS link configuration.
lvds_channel_mode:Specify LVDS channel mode (0=probe BIOS [default], 1=single-channel, 2=dual-channel) (int)
- - from /sbin/modinfo i915
+ - from /sbin/modinfo i915 - use <b>lvds_channel_mode=2</b> as a kernel option in grub.cfg.
</p>
</div>