[Intel-gfx] WARNING on i915 - intel_panel

[Daniel Vetter]

On Mon, Aug 11, 2014 at 12:38:41AM +0100, Pedro Ribeiro wrote:
> On 2 June 2014 21:15, Pedro Ribeiro <pedrib at gmail.com> wrote:
> > On 27 May 2014 08:15, Daniel Vetter <daniel at ffwll.ch> wrote:
> >> On Mon, May 26, 2014 at 9:44 PM, Pedro Ribeiro <pedrib at gmail.com> wrote:
> >>> Kern.log is attached, but as you can see it does not contain the same
> >>> verbose drm debug information as dmesg... Should I just keep piping
> >>> dmesg to a file and then cat it all together?
> >>> I never really understood why there are so many logs: kern, messages,
> >>> syslog, instead of a single central log.
> >>
> >> Indeed, that one isn't useful either :( Next idea: Increase the
> >> in-kernel dmesg buffer size and hope it all fits with log_buf_size=4M
> >> (on the kernel cmdline). Maybe you can go even higher, not sure.
> >> -Daniel
> >> --
> >> Daniel Vetter
> >> Software Engineer, Intel Corporation
> >> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
> >
> > Daniel, doesn't seem like that is working.
> >
> > I'll leave it be and try to test new kernels and see if it just goes
> > away. I'll report back if it doesn't.
> >
> > Regards,
> > Pedro
> 
> Hi Daniel,
> 
> the problem is still there with the latest 3.14.14. But the good news
> is that I have finally been able to get a full dmesg log!
> Please find it attached. I hope this helps and let me know what else I
> need to do to assist.
> 
> The log shows two hibernate-resume cycles, and you can see the bug
> being triggered at line 4274. As I said previously this looks like it
> doesn't affect the operation much, although it seems to happen very
> frequently as I do more hibernate cycles.

Yeah, log looks interesting, but I don't immediately see what's wrong. Can
you please fiel a new bug on bugs.freedeskopt.org against DRI -> DRM
(Intel) and please don't forget to put [regression] into the summary.

Also, if you manually disable the lvds with e.g.

$ xrandr --output LVDS1 --off ; xrandr --output LVDS1 --auto

does it happen, too? Or do you only see this over a hibernate cycle?

> PS: if I hibernate with a external monitor connected, and resume
> without that monitor connected, will the kernel handle it correctly?

Well the kernel won't do much, but it will generate a hotplug event to
inform userspace that the configuration changed. Then userspace needs to
figure out what to do - by default we keep pumping pixels to the screen
presuming that the cable fell out for a bit and that the user will replug.
But a good DE reconfigures or shows you a dialog box on one of the
remaining enabled screens.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch