linux-kernel - Re: [PATCH] drm/msm/mdp5: drop support for MSM8998, SDM630 and SDM660

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Message-ID: <92f0e801-032f-4c8a-8bb4-ecb3af48af0a@oss.qualcomm.com>
Date: Thu, 18 Dec 2025 14:54:15 +0100
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Cc: Alexey Minnekhanov <alexeymin@...tmarketos.org>,
        "marijn.suijten@...ainline.org" <marijn.suijten@...ainline.org>,
        Rob Clark <robin.clark@....qualcomm.com>,
        Dmitry Baryshkov
 <lumag@...nel.org>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Jessica Zhang <jesszhan0024@...il.com>, Sean Paul <sean@...rly.run>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Paul Sajna <sajattack@...tmarketos.org>,
        barnabas.czeman@...nlining.org
Subject: Re: [PATCH] drm/msm/mdp5: drop support for MSM8998, SDM630 and SDM660

On 12/18/25 2:49 PM, Dmitry Baryshkov wrote:
> On Thu, Dec 18, 2025 at 12:23:49PM +0100, Konrad Dybcio wrote:
>> On 12/17/25 5:34 PM, Dmitry Baryshkov wrote:
>>> On Wed, Dec 17, 2025 at 06:05:31PM +0300, Alexey Minnekhanov wrote:
>>>> On 11.12.2025 04:25, Dmitry Baryshkov wrote:
>>>>> Currently MDP5 3.x (MSM8998, SDM630 and SDM660) platforms are support
>>>>> by both DPU and MDP5 drivers. Support for them in the DPU driver is
>>>>> mature enough, so it's no longer sensible to keep them enabled in the
>>>>> MDP5 driver. Not to mention that MSM8998 never used an MDP5 compatible
>>>>> string. Drop support for the MDP5 3.x genration inside the MDP5
>>>>> driver and migrate those to the DPU driver only.
>>>>>
>>>>> Note: this will break if one uses the DT generated before v6.3 as they
>>>>> had only the generic, "qcom,mdp5" compatible string for SDM630 and
>>>>> SDM660. However granted that we had two LTS releases inbetween I don't
>>>>> think it is an issue.
>>>>>
>>>>
>>>> I've retested DPU driver on our downstream release based on 6.18 (by
>>>> using msm.prefer_mdp5=false kernel cmdline parameter) on all devices
>>>> at my disposal, and I can confirm DPU driver working fine an all SDM660,
>>>> SDM636 ones, but not on SDM630. Some logs from sdm630-sony-nile-pioneer
>>>> (Sony Xperia XA2):
>>>
>>> Unfortunately I only have SDM660 and video DSI usecase here. BTW: is
>>> your SDM636 / SDM660 using CMD or video panel?
>>>
>>>>
>>>> [    2.356546] msm_dpu c901000.display-controller: bound c994000.dsi (ops
>>>> dsi_ops [msm])
>>>> [    2.357328] adreno 5000000.gpu: GPU speedbin fuse 146 (0x92), mapped to
>>>> opp-supp-hw 0x4
>>>> [    2.364802] msm_dpu c901000.display-controller: bound 5000000.gpu (ops
>>>> a3xx_ops [msm])
>>>> [    2.444649] [drm:dpu_kms_hw_init:1173] dpu hardware revision:0x30030000
>>>> [    2.449793] [drm] Initialized msm 1.13.0 for c901000.display-controller
>>>> on minor 1
>>>> ...
>>>> [    2.911900] [drm:_dpu_encoder_phys_cmd_wait_for_ctl_start:654] [dpu
>>>> error]enc33 intf1 ctl start interrupt wait failed
>>>> [    2.911916] [drm:dpu_kms_wait_for_commit_done:525] [dpu error]wait for
>>>> commit done returned -22
>>>> ...
>>>> [    3.176171] [drm:_dpu_encoder_phys_cmd_wait_for_ctl_start:654] [dpu
>>>> error]enc33 intf1 ctl start interrupt wait failed
>>>> [    3.176367] [drm:dpu_kms_wait_for_commit_done:525] [dpu error]wait for
>>>> commit done returned -22
>>>>
>>>> Which results in horrendous ~3-5 fps in shell.
>>>>
>>>> The block "enc33 intf1 ctl start interrupt wait failed" + "wait for
>>>> commit done returned -22" is repeated few times per second whenever
>>>> the display is turned on, and stops when it's turned off.
>>>>
>>>> Meanwhile it is working fine using MDP5 driver (msm.prefer_mdp5=true).
>>>
>>> It's interesting. Would you please capture the devcoredump for the
>>> platform? There will be a lot of blocks, I'm interested in INTF_1, CTL
>>> and top_0.
>>>
>>> Also, as a debugging check, would you mind patching
>>> dpu_encoder_phys_cmd_wait_for_commit_done() so that it always calls
>>> dpu_encoder_phys_cmd_wait_for_tx_complete()? I will check if there are
>>> any differences for CTL_START and similar registers, but it will take
>>> some time.
>>>
>>>> Well, as fine as possible considering [1], using several FD_MESA_DEBUG
>>>> tricks to work around GPU issues.
>>>>
>>>> P.S. I have not yet tested MSM8998, but I can try if required
>>>
>>> As far as I remember, MDP5 on MSM8998 has never been wired (as in never
>>> committed to the DTSI). Angelo has enabled and Freebox people have
>>> tested DPU on MSM8998, but I think it was limited to video / HDMI
>>> usecases.
>>
>> I think we poked at both, back in the day (tm) and DPU worked on msm8998-
>> sony-maple (sharp,ls055d1sx04 cmd mode panel) with the funny CMD mode hack
>> (due to a register field not existing on <845?)
>>
>> https://github.com/SoMainline/linux/commit/14e0517e2fd5eee116a32db624b09856c60fa022
> 
> Ok, so my guess was correct and CTL_START is not present there. Checking
> the regmaps, there is no intr_start too. Let me cook the patchset.

FWIW it's not something I came up with.. But I can't fully recall the
original finder. Maybe it was one of the MSM8996/MSM8998/SDM845-mainline
contributors? It was difficult to find, so I'd like to credit the author
but I'm afraid I can't find it..

Konrad