Re: [PATCH v5 0/5] Add ARM Mali Midgard device tree bindings and gpu node for rk3288

[Guillaume Tucker <guillaume.tucker-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>]

Hi Randi,

On 09/05/17 08:45, Randy Li wrote:
>
>
> On 05/09/2017 03:40 PM, Guillaume Tucker wrote:
>> On 09/05/17 02:16, Randy Li wrote:
>>>
>>>
>>> On 05/09/2017 12:27 AM, Heiko Stübner wrote:
>>>> Am Mittwoch, 3. Mai 2017, 10:56:24 CEST schrieb Guillaume Tucker:
>>>>> The ARM Mali Midgard GPU kernel driver is only available
>>>>> out-of-tree and is not going to be merged in its current form.
>>>>> However, it would be useful to have its device tree bindings
>>>>> merged.  In particular, this would enable distributions to create
>>>>> working driver packages (dkms...) without having to patch the
>>>>> kernel.
>>>>>
>>>>> The bindings for the earlier Mali Utgard GPU family have already
>>>>> been merged, so this is essentially the same scenario but for
>>>>> newer GPUs (Mali-T604 ~ Mali-T880).
>>>>>
>>>>> This series of patches first imports the bindings from the latest
>>>>> driver release with some clean-up then adds a gpu node for the
>>>>> rk3288 SoC.  This was successfully tested on Radxa Rock2 Square,
>>>>> Firefly, Veyron Minnie and Jerry boards using Mali kernel driver
>>>>> r16p0 and r12p0 user-space binary.
>>> I won't suggest such combine. We meet some problems at mali 400 serial.
>>> I would suggest the kernel version would match the user library.
>>
>> Well, I can test it again with r12p0 kernel driver (out-of-tree)
>> if you want.  The user-space driver checks the version of the
>> kernel driver and gives up if it's not compatible.  With Midgard,
>> there's a range of versions that maintain kernel/userspace
>> compatibility unlike Utgard and older Midgard releases where they
>> had to exactly match.  Again, if there was a mismatch then the
>> user-space would fail to initialise and report an error.

> Anyway, could you verify the mali userspace library r13p0?

The latest user-space binary available from developer.arm.com for
rk3288 is 12p0.  Maybe Rockchip could make some new binaries
available to the public?

> Rockchip would use this version to offer the support of X11, wayland and gbm.

Sounds great, although windowing systems are quite far away from
GPU device tree bindings so I don't think this is too relevant
for this current patch series.

On a side note, it would be fantastic to get all this available
in Debian packages :)

>>> Also please notice there is rk3288w, the hardware version becomes r1p0.
>>
>> Sounds like a new SoC?  Does rk3288w affect rk3288 in any way?
> It is not a new SoC, just a new version of rk3288. It fixes a various of the chip bug of the rk3288.

I see.  I don't have access to any rk3288w platform but if you do
then I guess it would be nice if you could test these patches on
it :)  Also I'm not sure if all rk3288 device trees changes must
be tested on rk3288w, and this SoC is not mentioned anywhere in
the kernel (as far as I can tell).

Is there anything you think should block these current patches
which only claim to support rk3288 from being merged?

>> Unless it's a special case, it seems to me that any new SoC with
>> a Midgard GPU would need an extra vendor compatible string in the
>> binding documentation and maybe a separate gpu dt node.
>>
>>>> The actual devicetree parts are all Rockchip-specific, so I guess I'll just
>>>> pick up the whole series, including the binding doc, after the merge
>>>> window if nobody complains before that :-)
>>
>> Thanks!

Guillaume


P.S. kernel branch with a Mali driver I used for testing:
https://git.collabora.com/cgit/user/gtucker/linux.git/log/?h=linux-4.11-mali-dt-rk3288
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