Re: [PATCH v3 17/27] drm/msm/mdss: use new helper to set amsbc

Konrad Dybcio
2026-03-16T10:08:05Z

On 3/13/26 3:26 PM, Dmitry Baryshkov wrote:
> On Fri, Mar 13, 2026 at 11:19:59AM +0100, Konrad Dybcio wrote:
>> On 3/12/26 2:29 PM, Dmitry Baryshkov wrote:
>>> Use freshly defined helper instead of checking the UBWC version
>>> directly.
>>>
>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
>>> ---
>>> drivers/gpu/drm/msm/msm_mdss.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/msm_mdss.c b/drivers/gpu/drm/msm/msm_mdss.c
>>> index ca59bcdde7b2..04efc29f38cd 100644
>>> --- a/drivers/gpu/drm/msm/msm_mdss.c
>>> +++ b/drivers/gpu/drm/msm/msm_mdss.c
>>> @@ -188,7 +188,7 @@ static void msm_mdss_5x_setup_ubwc(struct msm_mdss *msm_mdss)
>>> if (qcom_ubwc_macrotile_mode(data))
>>> value |= MDSS_UBWC_STATIC_MACROTILE_MODE;
>>>
>>> - if (data->ubwc_enc_version == UBWC_3_0)
>>> + if (qcom_ubwc_enable_amsbc(data))
>>> value |= MDSS_UBWC_STATIC_UBWC_AMSBC;
>>
>> I know it's already there, but fwiw downstream doesn't seem to be
>> concerned with toggling AMSBC in MDSS (perhaps incorrectly?)
>
> Downstream enables it only for the cases where encoder and decoder
> use exactly UBWC 3.0. This is not completely correct as the bit doesn't
> exist for MDSS 6.x+. For 5.x this is equivalent to the code from the
> patch: enable AMSBC if targeting UBWC >= 3.0 (because MDSS 5.x don't
> support UBWC 4.0 or higher).

Right, this seems to indeed be the case

While trying to confirm that, I noticed that some lower-end MDSS 5.x
chips (like Talos) report UBWC3 in the register, but the MDSS docs say
they're UBWC2 - any idea?

Konrad