Hello Arthur Heymans,
I'd like you to do a code review. Please visit
https://review.coreboot.org/c/libgfxinit/+/35779
to review the following change.
Change subject: gma g45 config: Limit HDMI rate to 165MHz ......................................................................
gma g45 config: Limit HDMI rate to 165MHz
Tests with a 3440x1440 pixel display have shown that the dot clock was chosen much too high (we got either 720x1440 at half the rate or a completely garbled picture). Turns out, Linux' i915 limits the clock to the original DVI's 165MHz for 4th gen and earlier, so we'll do that too. This resulted in a stable picture with 3440x1440 @ 31Hz (the display even synchronized better on this than the configuration chosen by i915).
Change-Id: I30cb67feedd776148457101d1ca3e3b8538e672f Signed-off-by: Nico Huber nico.h@gmx.de --- M common/hw-gfx-gma-config.ads.template 1 file changed, 4 insertions(+), 1 deletion(-)
git pull ssh://review.coreboot.org:29418/libgfxinit refs/changes/79/35779/1
diff --git a/common/hw-gfx-gma-config.ads.template b/common/hw-gfx-gma-config.ads.template index 8711e54..f9d67aa 100644 --- a/common/hw-gfx-gma-config.ads.template +++ b/common/hw-gfx-gma-config.ads.template @@ -322,7 +322,10 @@
-- FIXME: Unknown for Broxton, Linux' i915 contains a fixme too :-D HDMI_Max_Clock_24bpp : constant Frequency_Type := - (if Haswell_On then 300_000_000 else 225_000_000); + (case Gen is + when Generation'First .. G45 => 165_000_000, + when Ironlake => 225_000_000, + when Haswell .. Generation'Last => 300_000_000);
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