Bug#658662: drm/i915: no signal via DisplayPort on Sandy Bridge since Linux 3.2
On Sat, Feb 04, 2012 at 06:31:13PM -0500, Peter Colberg wrote:
> Since upgrading to linux-image-3.2.0-1-amd64, an external display
> connected via DisplayPort to a Sandy Bridge onboard graphics card
> stopped working, and instead turns off reporting “DP no signal”.
Ok, I have finished the bisect, compiling and testing 17 kernels.
It seems the math in the i915 DisplayPort code got worse… ;-)
Peter
cd9dde44f47501394b9f0715b6a36a92aa74c0d0 is the first bad commit
commit cd9dde44f47501394b9f0715b6a36a92aa74c0d0
Author: Adam Jackson <ajax@redhat.com>
Date: Fri Oct 14 12:43:49 2011 -0400
drm/i915/dp: Fix the math in intel_dp_link_required
The previous code was confused about units, which is pretty reasonable
given that the units themselves are confusing.
Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
:040000 040000 3c0a0f38fc6482a401340e03fa3fbd687d11eda4 294673b782b3ecc93540f46f7721d385bd30cfac M drivers
# git bisect log
# bad: [805a6af8dba5dfdd35ec35dc52ec0122400b2610] Linux 3.2
# good: [c3b92c8787367a8bb53d57d9789b558f1295cc96] Linux 3.1
git bisect start 'v3.2' 'v3.1'
# bad: [68d99b2c8efcb6ed3807a55569300c53b5f88be5] Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
git bisect bad 68d99b2c8efcb6ed3807a55569300c53b5f88be5
# good: [efb8d21b2c6db3497655cc6a033ae8a9883e4063] Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
git bisect good efb8d21b2c6db3497655cc6a033ae8a9883e4063
# good: [8686a0e200419322654a75155e2e6f80346a1297] Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
git bisect good 8686a0e200419322654a75155e2e6f80346a1297
# bad: [f362f98e7c445643d27c610bb7a86b79727b592e] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/hch/vfs-queue
git bisect bad f362f98e7c445643d27c610bb7a86b79727b592e
# good: [ca836a25435ef1b9914840ed0a310c9b6ac261d1] Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
git bisect good ca836a25435ef1b9914840ed0a310c9b6ac261d1
# good: [c5c42360bc1cb14c7da3186683e9525b33b72656] vmwgfx: Don't pass unused arguments to do_dirty functions
git bisect good c5c42360bc1cb14c7da3186683e9525b33b72656
# bad: [5619a693965b291315685bdfe01a0246ebd7e41e] Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs
git bisect bad 5619a693965b291315685bdfe01a0246ebd7e41e
# bad: [82d165557ef094d4b4dfc05871aee618ec7102b0] drm/i915/dp: Fix eDP on PCH DP on CPT/PPT
git bisect bad 82d165557ef094d4b4dfc05871aee618ec7102b0
# good: [a9e2641dee52cae2db7688a749344365642a5e79] drm/i915: close PM interrupt masking races in the rps work func
git bisect good a9e2641dee52cae2db7688a749344365642a5e79
# good: [75770564c90c45618003267f4cdde4bbc090f1bd] drm/i915: use transcoder select bits on VGA and HDMI on CPT
git bisect good 75770564c90c45618003267f4cdde4bbc090f1bd
# good: [a487928908226df493a3ce145ecf4bb39296714e] drm/i915: remove transcoder PLL mashing from mode_set per specs
git bisect good a487928908226df493a3ce145ecf4bb39296714e
# bad: [a2006cf5a7ad3463e7c1e9da2c4bc90499427558] drm/i915: read full receiver capability field during DP hot plug
git bisect bad a2006cf5a7ad3463e7c1e9da2c4bc90499427558
# good: [f52c619a590fa75276c07dfcaf380dee53e4ea4c] drm/i915/panel: Always record the backlight level again (but cleverly)
git bisect good f52c619a590fa75276c07dfcaf380dee53e4ea4c
# bad: [dc22ee6fc18ce0f15424e753e8473c306ece95c1] drm/i915/dp: Remove eDP special cases from bandwidth checks
git bisect bad dc22ee6fc18ce0f15424e753e8473c306ece95c1
# bad: [cd9dde44f47501394b9f0715b6a36a92aa74c0d0] drm/i915/dp: Fix the math in intel_dp_link_required
git bisect bad cd9dde44f47501394b9f0715b6a36a92aa74c0d0
Reply to: