Re: [Intel-gfx] [git pull] drm fixes

Xi Ruoyao
2015-03-25T03:49:47Z

On 03/25/2015 at 12:54 AM, Josh Boyer wrote:
> On Tue, Mar 24, 2015 at 12:49 PM, Daniel Vetter <daniel@ffwll.ch> wrote:
>> On Tue, Mar 24, 2015 at 05:48:31PM +0100, Daniel Vetter wrote:
>>> On Tue, Mar 24, 2015 at 12:10:28PM -0400, Josh Boyer wrote:
>>>> On Tue, Mar 24, 2015 at 10:46 AM, Josh Boyer <jwboyer@fedoraproject.org> wrote:
>>>>> On Tue, Mar 24, 2015 at 10:34 AM, Daniel Vetter <daniel@ffwll.ch> wrote:
>>>>>> On Tue, Mar 24, 2015 at 10:22:30AM -0400, Josh Boyer wrote:
>>>>>>> On Tue, Mar 24, 2015 at 9:57 AM, Josh Boyer <jwboyer@fedoraproject.org> wrote:
>>>>>>>> On Tue, Mar 24, 2015 at 9:40 AM, Daniel Vetter <daniel@ffwll.ch> wrote:
>>>>>>>>> On Tue, Mar 24, 2015 at 09:15:32AM -0400, Josh Boyer wrote:
>>>>>>>>>> On Tue, Mar 24, 2015 at 3:32 AM, Daniel Vetter <daniel@ffwll.ch> wrote:
>>>>>>>>>>> On Mon, Mar 23, 2015 at 02:34:27PM -0400, Josh Boyer wrote:
>>>>>>>>>>>> On Mon, Mar 23, 2015 at 11:33 AM, Josh Boyer <jwboyer@fedoraproject.org> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>> <snip>
>>>>>>>>>>>>
>>>>>>>>>>>>>> Xi Ruoyao (1):
>>>>>>>>>>>>>> drm/i915: Ensure plane->state->fb stays in sync with plane->fb
>>>>>>>>>>>> Turns out to be that commit.
>>>>>>>>>>>>
>>>>>>>>>>>> git bisect start 'drivers/gpu/drm/i915/'
>>>>>>>>>>>> # good: [b314acaccd7e0d55314d96be4a33b5f50d0b3344] Merge branch
>>>>>>>>>>>> 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
>>>>>>>>>>>> git bisect good b314acaccd7e0d55314d96be4a33b5f50d0b3344
>>>>>>>>>>>> # bad: [bc465aa9d045feb0e13b4a8f32cc33c1943f62d6] Linux 4.0-rc5
>>>>>>>>>>>> git bisect bad bc465aa9d045feb0e13b4a8f32cc33c1943f62d6
>>>>>>>>>>>> # bad: [319c1d420a0b62d9dbb88104afebaabc968cdbfa] drm/i915: Ensure
>>>>>>>>>>>> plane->state->fb stays in sync with plane->fb
>>>>>>>>>>>> git bisect bad 319c1d420a0b62d9dbb88104afebaabc968cdbfa
>>>>>>>>>>>> # first bad commit: [319c1d420a0b62d9dbb88104afebaabc968cdbfa]
>>>>>>>>>>>> drm/i915: Ensure plane->state->fb stays in sync with plane->fb
>>>>>>>>>>>>
>>>>>>>>>>>> Doing a straight revert on top of 4.0-rc5 makes things work again,
>>>>>>>>>>>> albeit with the WARN_ON(obj->frontbuffer_bits) splat still being
>>>>>>>>>>>> there.
>>>>>>>>>>> Can you please test the tip of drm-fixes:
>>>>>>>>>>>
>>>>>>>>>>> commit 8218c3f4df3bb1c637c17552405039a6dd3c1ee1
>>>>>>>>>>> Author: Daniel Vetter <daniel.vetter@ffwll.ch>
>>>>>>>>>>> Date: Fri Feb 27 12:58:13 2015 +0100
>>>>>>>>>>>
>>>>>>>>>>> drm: Fixup racy refcounting in plane_force_disable
>>>>>>>>>>>
>>>>>>>>>>> http://cgit.freedesktop.org/~airlied/linux/commit/?h=drm-fixes&id=8218c3f4df3bb1c637c17552405039a6dd3c1ee1
>>>>>>>>>>>
>>>>>>>>>>> Because fumble that patch didn't make it to drm-fixes a while ago and
>>>>>>>>>>> instead landed in drm-next.
>>>>>>>>>> That seems to have helped with totally different issues a macbook I
>>>>>>>>>> have was seeing. However, it still doesn't fix the issue with the
>>>>>>>>>> Celeron based NUC machine.
>>>>>>>>>>
>>>>>>>>>> I built a kernel based on Linus' latest tree as of this morning,
>>>>>>>>>> without reverting 319c1d4 and adding the commit you pointed to. The
>>>>>>>>>> NUC still won't boot without HDMI connected. With HDMI connected I
>>>>>>>>>> still see the trace below. If I do the blacklist and then insmod
>>>>>>>>>> dance with HDMI unplugged it shows the same spew I reported yesterday
>>>>>>>>>> which starts with the same backtrace.
>>>>>>>>>>
>>>>>>>>>> I'll try building a kernel with 319c1d4 reverted + your patch. I
>>>>>>>>>> suspect things will work fine with that combination because the two
>>>>>>>>>> issues are unrelated.
>>>>>>>>> Can you please boot with drm.debug=0xff for the below case and grab
>>>>>>>>> complete dmesg? There'll be a lot of crap in the logs, you might need to
>>>>>>>>> blow up the logbuf size massively. But that log should contain everything
>>>>>>>>> I need to figure out where that framebuffer we're blowing up on is going.
>>>>>>>> I provided both with HDMI attached and without (via insmod). If you
>>>>>>>> want them emailed directly let me know, but they were large.
>>>>>>>>
>>>>>>>> Boot with drm.debug=0xff and HDMI connected:
>>>>>>>>
>>>>>>>> https://jwboyer.fedorapeople.org/pub/drm-ff-dmesg.txt
>>>>>>>>
>>>>>>>> Boot with drm.debug=0xff without HDMI connected and i915 loaded via
>>>>>>>> manual insmod after boot:
>>>>>>>>
>>>>>>>> https://jwboyer.fedorapeople.org/pub/drm-ff-no-hdmi-insmod.txt
>>>>>>> Here's one more from the macbook I mentioned. It's showing the same
>>>>>>> kref.h splat:
>>>>>>>
>>>>>>> https://jwboyer.fedorapeople.org/pub/drm-ff-macbook.txt
>>>>>> Ok there's at least one fixup for which we've failed to apply when porting
>>>>>> the fb refcounting fix from -next. Can you please cherry-pick
>>>>>>
>>>>>> commit f55548b5af87ebfc586ca75748947f1c1b1a4a52
>>>>>> Author: Damien Lespiau <damien.lespiau@intel.com>
>>>>>> Date: Thu Feb 5 18:30:20 2015 +0000
>>>>>>
>>>>>> drm/i915: Don't try to reference the fb in get_initial_plane_config()
>>>>>>
>>>>>> From linux-next?
>>>>> Yes, building now. Will let you know as soon as I test it on both machines.
>>>> OK, with that commit applied I no longer get the kref.h splat and the
>>>> NUC machine boots headless. I still see the backtrace below on both
>>>> the NUC and the macbook. I have a copy of it with drm.debug=0xff from
>>>> the NUC here:
>>>>
>>>> https://jwboyer.fedorapeople.org/pub/nuc-drm-debug-ff-with-fixes.txt
>>>>
>>>> Getting better at least :).
>>> Ok thanks for testing. I'll look at that one tomorrow, wasted too much
>>> time with trying to resurrect a few machines that should have matched the
>>> common parts of what goes wrong here.
>>>
>>> Jani, can you please cherry-pick the above commit to -fixes?
>> Actually add Jani this time around ...
>> -Daniel
>>
>>> One more question: Is the frontbuffer_bits splat now also gone? That was
>>> the one I have no clue about, but since somewhere around 4.0-rc it started
>>> poppping up in a few places ... Thus far it was always the canary for some
>>> other bug though.
> As far as I can tell, it's gone. I don't see it on any of my i915
> machines running the kernel with those two patches. I'll keep an eye
> out for it as we work through 4.0-rcX.
>
> josh
It's fortunately my computer didn't stuck. But it's unfortuantely
my patch causing so much trouble. I should've research commit
in linux-next more before applying it to mainline.

I found many WARNINGs in kernel log after Josh reported this bug.
I will try Damien's solution.

--
Xi Ruoyao
School of Aerospace Science and Technology
Xidian University, Xi'an, China