Re: [PATCH v3 1/6] drm/msm/a6xx: Retrieve gmu core range by index

[Rob Clark]

On Thu, Dec 4, 2025 at 5:30 AM Konrad Dybcio
<konrad.dybcio@xxxxxxxxxxxxxxxx> wrote:
>
> On 12/4/25 2:10 PM, Akhil P Oommen wrote:
> > On 11/22/2025 7:08 PM, Konrad Dybcio wrote:
> >> On 11/21/25 10:52 PM, Akhil P Oommen wrote:
> >>> Some GPUs like A612 doesn't use a named register range resource. This
> >>> is because the reg-name property is discouraged when there is just a
> >>> single resource.
> >>>
> >>> To address this, retrieve the 'gmu' register range by its index. It is
> >>> always guaranteed to be at index 0.
> >>>
> >>> Signed-off-by: Akhil P Oommen <akhilpo@xxxxxxxxxxxxxxxx>
> >>> ---
> >>>  drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 14 ++++++--------
> >>>  1 file changed, 6 insertions(+), 8 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
> >>> index 5903cd891b49..9662201cd2e9 100644
> >>> --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
> >>> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
> >>> @@ -2029,21 +2029,19 @@ static int cxpd_notifier_cb(struct notifier_block *nb,
> >>>     return 0;
> >>>  }
> >>>
> >>> -static void __iomem *a6xx_gmu_get_mmio(struct platform_device *pdev,
> >>> -           const char *name, resource_size_t *start)
> >>> +static void __iomem *a6xx_gmu_get_mmio(struct platform_device *pdev, resource_size_t *start)
> >>
> >> Can we drop this and just use devm_platform_get_and_ioremap_resource()?
> >
> > This API seems to lock the io region and fails with -EBUSY if the region
> > is already in use. I am worried it may regress other chipsets. So, I
> > dropped this idea at the last moment.
>
> Is there any specific platform where this would be an issue?

IIRC we've had this problem before and ended up reverting a similar
change, due to gpucc and gpu overlap

BR,
-R