ARMSOC X11 plugin issues

[Jasper St. Pierre]

ARMSOC isn't a well-written driver, basically. Is there a reason
you're not using modesetting if it works better for you?

On Thu, Mar 31, 2016 at 1:54 AM, Maxime Ripard
<maxime.ripard at free-electrons.com> wrote:
> On Wed, Mar 23, 2016 at 10:17:05PM +0100, Maxime Ripard wrote:
>> Hi David, Marico,
>>
>> I've been developping a DRM/KMS driver for the Allwinner SoCs[1], with
>> an additional patch to allocate GPU buffers [2]. Since those SoCs also use
>> a Mali GPU, using the armsoc X11 plugin seemed like a logical choice.
>>
>> I added support for the driver based on the 1.4 plugin [3], and
>> started using it, which turned out pretty well, we get something
>> displayed, GLES works, good.
>>
>> However, after testing it for a while, the first thing we noticed was
>> that some (large) buffer allocations would start to fail. Indeed, the
>> plugin seems to do a lot of rather small (and for most temporary ?)
>> buffer allocations, which eventually depletes the reserved memory
>> pool. The allocation then fails, and the application crashes.
>>
>> Then, we noticed (using xfce4, on debian jessie) that the systray
>> icons were not displayed for some reason. There's also some game
>> (alex4 [4]), that starts, runs, but the window content remains black
>> (but it remains interactive, audio plays and if we take a screenshot,
>> the content is on the image, but the screen remains black).
>>
>> The weird thing about it is that when using the X generic modesetting
>> plugin, everything starts to work. It seems to be allocating only one
>> buffer per plane, so we never have the memory allocation
>> failures. Which raises my first question: why is the armsoc plugin
>> behaving differently there?
>>
>> Then the graphics issues we were seeing are not there anymore, which
>> seems to indicate that it's related to the plugin. I'm a bit oblivious
>> to how X works exactly, and how applications interacts with it, but on
>> the ioctl side, nothing really stands out. Let me know if you need any
>> more tests or logs or anything.
>
> Anyone ?
>
> Thanks,
> Maxime
>
>
>
> --
> Maxime Ripard, Free Electrons
> Embedded Linux, Kernel and Android engineering
> http://free-electrons.com
>
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-- 
  Jasper