Re: [Intel-gfx] Critical regression in 4.7-rcX
From: Larry Finger
Date: Fri Jul 15 2016 - 13:26:37 EST
On 07/15/2016 11:36 AM, Bish, Jim wrote:
On Fri, 2016-07-15 at 10:34 -0500, Larry Finger wrote:
On 07/15/2016 09:43 AM, Ville SyrjÃlà wrote:
On Fri, Jul 15, 2016 at 04:27:27PM +0200, Daniel Vetter wrote:
On Fri, Jul 15, 2016 at 8:55 AM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
On Thu, 14 Jul 2016, Larry Finger wrote:
To anyone keeping track of regressions in kernel 4.7, I call
your attention to
https://bugs.freedesktop.org/show_bug.cgi?id=96675.
This bug causes driver i915 to fail to connect to the
display, and results in
a blank screen as soon as the kernel is loaded. The only way
to operate with
kernel 4.7 is to add "nomodeset" to the command line. The
problem was bisected
to commit f21a21983ef13a ("drm/i915: Splitting
intel_dp_detect").
Daniel? Jani? Time to revert?
Yup. Means that I'll get to revert a pile of patches (plus even
more
in -next), but that's what we get for not handling regressions
timely.
Dave poked me about the same bug already too. But will take a few
days
until the pull is in your inbox I guess.
I attached a oneliner to the bug today, that I *think* should fix
the
problem.
After I checked out the problem commit and built that kernel with the
one-line
patch, the display works; however, mainline still fails. I am
currently
bisecting to find what other commit fails. At a minimum, we should be
able to
reduce the number of commits that need reverting.
Larry
I was seeing the same issue Linus reported but very sporadically.
Assumed it was due to my wierd configuration - eDP + usb type c -> MST
hub -> DVI KVM -> dual head HDMI. Checked out the one liner - works
for me but I guess there are still other failures.
I'm not sure what I did wrong before, but when I retested mainline with the one
liner, it now works. Once that is pushed to mainline, the bug should be fixed.
Sorry for any confusion.
Larry