Added workaround for Mali 400 corrupting frame buffers upon discard.

Added workaround for Mali 400 corrupting frame buffers upon discard.

R=aelias@chromium.org
BUG=449488

[David Yen, 2015-04-06 23:27:57]

dyen@chromium.org changed reviewers:
+ sievers@chromium.org

[David Yen, 2015-04-06 23:27:57]

+sievers

[no sievers, 2015-04-06 23:32:15]

lgtm

But given that we just noticed this for two different vendors, you sure the
corruption is not our bug?

[David Yen, 2015-04-06 23:39:53]

On 2015/04/06 23:32:15, sievers wrote:
> lgtm
> 
> But given that we just noticed this for two different vendors, you sure the
> corruption is not our bug?

Both vendors are exhibiting different bugs. The qualcomm one is dropping draw
calls, and the Mali400 is corrupting memory.

Also, it was reported that the Mali400 bug was fixed so this only occurs on
older drivers. Is there a way to filter on driver numbers? Isn't it part of the
GL string?

[no sievers, 2015-04-06 23:50:49]

On 2015/04/06 23:39:53, David Yen wrote:
> On 2015/04/06 23:32:15, sievers wrote:
> > lgtm
> > 
> > But given that we just noticed this for two different vendors, you sure the
> > corruption is not our bug?
> 
> Both vendors are exhibiting different bugs. The qualcomm one is dropping draw
> calls, and the Mali400 is corrupting memory.
> 
> Also, it was reported that the Mali400 bug was fixed so this only occurs on
> older drivers. Is there a way to filter on driver numbers? Isn't it part of
the
> GL string?

You can look at the strings and try.
You might have to revisit our driver version string formatting code for Android.
It was added to specifically for Qualcomm.

[David Yen, 2015-04-07 16:27:24]

On 2015/04/06 23:50:49, sievers wrote:
> On 2015/04/06 23:39:53, David Yen wrote:
> > On 2015/04/06 23:32:15, sievers wrote:
> > > lgtm
> > > 
> > > But given that we just noticed this for two different vendors, you sure
the
> > > corruption is not our bug?
> > 
> > Both vendors are exhibiting different bugs. The qualcomm one is dropping
draw
> > calls, and the Mali400 is corrupting memory.
> > 
> > Also, it was reported that the Mali400 bug was fixed so this only occurs on
> > older drivers. Is there a way to filter on driver numbers? Isn't it part of
> the
> > GL string?
> 
> You can look at the strings and try.
> You might have to revisit our driver version string formatting code for
Android.
> It was added to specifically for Qualcomm.

The Mali400 does not advertise the driver version in the GL_VERSION string
unfortunately.

Also aelias has also completed this CL in his version
(https://codereview.chromium.org/1068573004/) so I will be closing this one.