On Tue, Sep 26, 2023 at 08:24:36PM +0200, Konrad Dybcio wrote:
>
> When opp-supported-hw is present under an OPP node, but no form of
> opp_set_supported_hw() has been called, that OPP is ignored by the API
> and marked as unsupported.
>
> Before Commit c928a05e4415 ("drm/msm/adreno: Move speedbin mapping to
> device table"), an unknown speedbin would result in marking all OPPs
> as available, but it's better to avoid potentially overclocking the
> silicon - the GMU will simply refuse to power up the chip.
>
> Currently, the Adreno speedbin code does just that (AND returns an
> invalid error, (int)UINT_MAX). Fix that by defaulting to speedbin 0
> (which is conveniently always bound to fuseval == 0).
Wish we documented somewhere that we should reserve BIT(0) for fuse
val=0 always and assume that would be the super SKU.
Reviewed-by: Akhil P Oommen <quic_akhilpo@xxxxxxxxxxx>
-Akhil
>
> Fixes: c928a05e4415 ("drm/msm/adreno: Move speedbin mapping to device table")
> Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
> ---
> drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> index d4e85e24002f..522ca7fe6762 100644
> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> @@ -2237,7 +2237,7 @@ static int a6xx_set_supported_hw(struct device *dev, const struct adreno_info *i
> DRM_DEV_ERROR(dev,
> "missing support for speed-bin: %u. Some OPPs may not be supported by hardware\n",
> speedbin);
> - return UINT_MAX;
> + supp_hw = BIT(0); /* Default */
> }
>
> ret = devm_pm_opp_set_supported_hw(dev, &supp_hw, 1);
>
> --
> 2.42.0
>
