From: Jani Nikula <jani.nikula@linux.intel.com>
To: Matthew Brost <matthew.brost@intel.com>, Hugh Dickins <hughd@google.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
intel-gfx@lists.freedesktop.org,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
Vinay Belgaumkar <vinay.belgaumkar@intel.com>,
Michal Wajdeczko <michal.wajdeczko@intel.com>,
Sujaritha Sundaresan <sujaritha.sundaresan@intel.com>,
John Harrison <John.C.Harrison@intel.com>,
Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>,
Matt Roper <matthew.d.roper@intel.com>,
Lucas De Marchi <lucas.demarchi@intel.com>,
Dave Airlie <airlied@gmail.com>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
Pavel Machek <pavel@denx.de>,
linux-kernel@vger.kernel.org
Subject: Re: 5.15-rc1 i915 blank screen booting on ThinkPads
Date: Sat, 18 Sep 2021 01:52:48 +0300 [thread overview]
Message-ID: <87k0jevmpr.fsf@intel.com> (raw)
In-Reply-To: <20210917213032.GA34270@jons-linux-dev-box>
On Fri, 17 Sep 2021, Matthew Brost <matthew.brost@intel.com> wrote:
> On Fri, Sep 17, 2021 at 02:26:48PM -0700, Hugh Dickins wrote:
>> On Thu, 16 Sep 2021, Jani Nikula wrote:
>> > On Thu, 16 Sep 2021, Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> wrote:
>> > > On 16/09/2021 05:37, Hugh Dickins wrote:
>> > >> Two Lenovo ThinkPads, old T420s (2011), newer X1 Carbon 5th gen (2017):
>> > >> i915 working fine on both up to 5.14, but blank screens booting 5.15-rc1,
>> > >> kernel crashed in some way.
>> ...
>> > > Kernel logs with drm.debug=0xe, with the broken black screen state,
>> > > would probably answer a lot of questions if you could gather it from
>> > > both machines?
>> >
>> > And for that, I think it's best to file separate bugs at [1] and attach
>> > the logs there. It helps keep the info in one place. Thanks.
>> >
>> > BR,
>> > Jani.
>> >
>> > [1] https://gitlab.freedesktop.org/drm/intel/issues/new
>>
>> Thanks for the quick replies: but of course, getting kernel logs was
>> the difficult part, this being bootup, with just a blank screen, and
>> no logging to disk at this stage. I've never needed it before, but
>> netconsole to the rescue.
>>
>> Problem then obvious, both machines now working,
>> please let me skip the bug reports, here's a patch:
>>
>
> Thanks for finding / fixing this Hugh. I will post this patch in a way
> our CI system can understand.
Thanks indeed!
Matt, please get rid of the BUG_ON while at it, and make it a
WARN. Oopsing doesn't do anyone any good.
BR,
Jani.
>
> Matt
>
>> [PATCH] drm/i915: fix blank screen booting crashes
>>
>> 5.15-rc1 crashes with blank screen when booting up on two ThinkPads
>> using i915. Bisections converge convincingly, but arrive at different
>> and surprising "culprits", none of them the actual culprit.
>>
>> netconsole (with init_netconsole() hacked to call i915_init() when
>> logging has started, instead of by module_init()) tells the story:
>>
>> kernel BUG at drivers/gpu/drm/i915/i915_sw_fence.c:245!
>> with RSI: ffffffff814d408b pointing to sw_fence_dummy_notify().
>> I've been building with CONFIG_CC_OPTIMIZE_FOR_SIZE=y, and that
>> function needs to be 4-byte aligned.
>>
>> Fixes: 62eaf0ae217d ("drm/i915/guc: Support request cancellation")
>> Signed-off-by: Hugh Dickins <hughd@google.com>
>> ---
>>
>> drivers/gpu/drm/i915/gt/intel_context.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> --- a/drivers/gpu/drm/i915/gt/intel_context.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_context.c
>> @@ -362,6 +362,7 @@ static int __intel_context_active(struct
>> return 0;
>> }
>>
>> +__aligned(4) /* Respect the I915_SW_FENCE_MASK */
>> static int sw_fence_dummy_notify(struct i915_sw_fence *sf,
>> enum i915_sw_fence_notify state)
>> {
--
Jani Nikula, Intel Open Source Graphics Center
next prev parent reply other threads:[~2021-09-17 22:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-16 4:37 5.15-rc1 i915 blank screen booting on ThinkPads Hugh Dickins
2021-09-16 8:44 ` Tvrtko Ursulin
2021-09-16 10:17 ` Jani Nikula
2021-09-17 21:26 ` Hugh Dickins
2021-09-17 21:30 ` Matthew Brost
2021-09-17 22:52 ` Jani Nikula [this message]
2021-09-17 23:29 ` Matthew Brost
2021-09-18 0:22 ` Hugh Dickins
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