Re: [PATCH v2 0/2] Exynos850 GPU support

[Thomas Turner <tturner@lineageos.org>]

On 26/08/2026 20:02, Alexey Klimov wrote:
> On Tue Aug 25, 2026 at 10:05 PM BST, Thomas Turner wrote:
>> Hi Sam and Alexey,
>>
>> On 19/08/2026 20:51, Sam Protsenko wrote:
>>> Can you please tell us a bit about how you tested this patch, and on
>>> which board? As DPU is not currently enabled on Exynos850 SoC, I'm not
>>> sure how exactly GPU can be useful. If you have a use case or a
>>> testing procedure we can run on the E850-96 board, please share.
>>>
>>
>> Sam, Alexey could you please test GPU on the E850-96 board by following
>> these instructions:
>>
>> 1) Apply this patch series locally
>> 2) Change status="disabled"; to status="okay";
>> 3) Make sure these configs are enabled:
>> CONFIG_DRM_SIMPLEDRM=y
>> CONFIG_DRM_PANFROST=y
>> 4) In terms of regulators we set up a basic mali regulator via our
>> secondary bootloader [1] and configured with this dts setup [2], NOTE
>> you may be able to get away with a dummy regulator so try that first.
>> If not I am sure you can replicate something simple with u-boot PMIC.
>> 5) Boot a GUI, I saw Debian was used for the bring-up, that should work
>> 6) Run the following command:
>> $ dmesg | grep "panfrost"
>> 7) Compare that to the output at [3]
> 
> Your email subject still seems to be null.
> 
> [   15.206193] panfrost 11500000.gpu: clock rate = 377000000
> [   15.206322] panfrost 11500000.gpu: error -ENODEV: _opp_set_regulators: no regulator (mali) found
> [   15.206513] panfrost 11500000.gpu: supply mali not found, using dummy regulator
> [   15.206840] panfrost 11500000.gpu: mali-g52 id 0x7212 major 0x0 minor 0x0 status 0x0
> [   15.213137] panfrost 11500000.gpu: features: 00000000,00000df7, issues: 00000000,00000400
> [   15.221271] panfrost 11500000.gpu: Features: L2:0x07100206 Shader:0x00000000 Tiler:0x00000809 Mem:0x1 MMU:0x00002830 AS:0xff JS:0x7
> [   15.233080] panfrost 11500000.gpu: shader_present=0x1 l2_present=0x1
> [   15.240488] panfrost 11500000.gpu: [drm] Using Transparent Hugepage
> [   15.250497] [drm] Initialized panfrost 1.6.0 for 11500000.gpu on minor 0

You seemed to have missed out step (4) of my instructions, if you set-up
regulators correctly this error will disappear.

> [root@e850usb ~]# uname -a
> Linux e850usb 7.2.0-next-20260825-00009-g647b48e80572-dirty #8 SMP PREEMPT Wed Aug 26 17:05:45 BST 2026 aarch64 GNU/Linux
> 
> I have different DRM_SIMPLEDRM options and related  enabled but nothing
> pops up via HDMI (at least I tried simple xorg-server things).
> Is it possible that your bootloader initilises some framebuffer and inserts
> it into DTB that passed to kernel? Or you have some other pieces in
> kernel/dt that implement missing functionality?

Our bootloader does intialise a framebuffer, and we have a node in our device
tree which makes it usable. Not sure how exactly the e850-96 device sets
things up but you can take a look at our fork if you want, [1].

> Here it seems there are no outputs:
> [root@e850usb ~]# ls -al /dev/fb*
> ls: cannot access '/dev/fb*': No such file or directory
> 
> and there no simle framebuffer or related logs. "DPU is not currently
> enabled on Exynos850 SoC" looks like the reason.

hm, I am pretty sure our bootloader configures DPU for us so that might be
why it works for us and not for you.

> Panfrost itself seems to be alive though:
> 
> [root@e850usb ~]# eglinfo -B
> GBM platform:
> EGL API version: 1.5
> EGL vendor string: Mesa Project
> EGL version string: 1.5
> EGL client APIs: OpenGL OpenGL_ES
> OpenGL core profile vendor: Mesa
> OpenGL core profile renderer: Mali-G52 MC1 (Panfrost)
> OpenGL core profile version: 3.1 Mesa 26.2.1-arch1.1
> OpenGL core profile shading language version: 1.40
> OpenGL compatibility profile vendor: Mesa
> OpenGL compatibility profile renderer: Mali-G52 MC1 (Panfrost)
> OpenGL compatibility profile version: 3.1 Mesa 26.2.1-arch1.1
> OpenGL compatibility profile shading language version: 1.40
> OpenGL ES profile vendor: Mesa
> OpenGL ES profile renderer: Mali-G52 MC1 (Panfrost)
> OpenGL ES profile version: OpenGL ES 3.1 Mesa 26.2.1-arch1.1
> OpenGL ES profile shading language version: OpenGL ES GLSL ES 3.10
> 
> Best regards,
> Alexey

Best Regards,
Tom

[1] https://github.com/samsungexynos850/linux/commits/master