On Fri, Jun 8, 2012 at 11:57 PM, Linus Torvalds torvalds@linux-foundation.org wrote:
This breaks things for me. Bisect says:
9e612a008fa7fe493a473454def56aa321479495 is the first bad commit commit 9e612a008fa7fe493a473454def56aa321479495 Author: Chris Wilson chris@chris-wilson.co.uk Date: Thu May 31 13:08:53 2012 +0100
drm/i915/crt: Do not rely upon the HPD presence pin
Whilst most monitors do wire up the HPD presence pin, it seems quite a few KVM do not. Therefore if we simply rely on the HPD pin being asserted to indicate a connected monitor we fail miserable, so fall back to performing a DCC query for the EDID.
Reported-and-tested-by: Matthieu LAVIE boiteamadmax@hotmail.com Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=50501 Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch
And the symptoms are that it boots in what appears to be the correct mode for my monitor (1920x1200), but when X starts it changes to 1024x768 mode.
Which is not good, and not useful.
The bad kernel has this in Xorg.0.log:
[ 12.796] (II) intel(0): EDID for output VGA1 [ 12.796] (II) intel(0): Printing probed modes for output VGA1 [ 12.796] (II) intel(0): Modeline "1024x768"x60.0 65.00 1024 1048 1184 1344 768 771 777 806 -hsync -vsync (48.4 kHz e) [ 12.796] (II) intel(0): Modeline "800x600"x60.3 40.00 800 840 968 1056 600 601 605 628 +hsync +vsync (37.9 kHz e) [ 12.796] (II) intel(0): Modeline "800x600"x56.2 36.00 800 824 896 1024 600 601 603 625 +hsync +vsync (35.2 kHz e) [ 12.796] (II) intel(0): Modeline "848x480"x60.0 33.75 848 864 976 1088 480 486 494 517 +hsync +vsync (31.0 kHz e) [ 12.796] (II) intel(0): Modeline "640x480"x59.9 25.18 640 656 752 800 480 489 492 525 -hsync -vsync (31.5 kHz e)
which is pure and utter garbage. I think it's the "default modes" for the non-EDID case, and has nothing to do with actual hardware.
The good kernel doesn't have those incorrect and bogus probed modes, and just has the correct HDMI1 (that the bad kernel *also* has, of course).
I have reverted that commit as obviously broken, since I'm not going to release an -rc2 that doesn't even work for me (and since it *is* obviously broken).
I've looked again through the code and with this patch we can fall through to the gen2/3 load detect code, which likely results totally bogus results for anything never (where we've previously relied exclusively on the hotplug pins). Sorry for not catching this when I've reviewed this patch for -fixes. Hence for the revert:
Acked-by: Daniel Vetter daniel.vetter@ffwll.ch
-Daniel