[Mesa-dev] [PATCH v3 3/3] egl/android: Add DRM node probing and filtering

[Amit Pundir]

On 14 June 2018 at 00:44, Rob Herring <robh at kernel.org> wrote:
> On Wed, Jun 13, 2018 at 12:19 PM, Amit Pundir <amit.pundir at linaro.org> wrote:
>> On 13 June 2018 at 20:45, Rob Herring <robh at kernel.org> wrote:
>>>
>>> +Amit and John
>>>
>>> On Sat, Jun 9, 2018 at 11:27 AM, Robert Foss <robert.foss at collabora.com> wrote:
>>> > This patch both adds support for probing & filtering DRM nodes
>>> > and switches away from using the GRALLOC_MODULE_PERFORM_GET_DRM_FD
>>> > gralloc call.
>>> >
>>> > Currently the filtering is based just on the driver name,
>>> > and the desired name is supplied using the "drm.gpu.vendor_name"
>>> > Android property.
>>>
>>> There's a potential issue with this whole approach and that is
>>> SELinux. With the way SELinux locks down accesses, getting probing
>>> thru device files to work can be a pain. It may be better now than the
>>> prior version because sysfs is not probed. I'll leave it to Amit or
>>> John to comment.
>>
>> Right.. so ICYMI, this patch is already pulled into external/mesa3d
>> project of AOSP and I stumbled upon one such /dev/dri/ access denial
>> on db820c recently.
>
> A prior version of the patch series which accesses sysfs too (via libdrm).
>
>>
>> In AOSP, zygote spawned apps already have access to GPU device nodes
>> in the form of /dev/gpu_device file, but the missing part is the
>
> It's "gpu_device" in terms a a SELinux context, right? Not an actual /dev path?

Yes in SELinux context, it is not an actual /dev/ path.

Regards,
Amit Pundir

>
>> open-read access to "/dev/dri/" which need to be allowed explicitly.
>
> Or we need a way to just open a specific device.
>
> Rob