On Wed, May 14, 2025 at 05:10:35PM +0200, Konrad Dybcio wrote:
> From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
>
> In preparation to resolve the issue of hardcoding HBB, throw a warning
> if the value is being overwritten in the GPU driver.
>
> The HBB value is directly correlated with the memory configuration.
> On platforms where more than one is supported, the value must differ
> for proper functioning of the hardware, but it also must be consistent
> across all UBWC producers/consumers.
>
> On platforms supporting only a single DRAM setup, the value may still
> be wrong, or at least inconsistent.
>
> Print a warning to help catch such cases, until we declare full trust
> to the central database.
>
> Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> ---
> drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> index eaf468b67f97ff153e92a73a45581228fcf75e46..ab812338739568d5908ca439e5c53e230a02de5d 100644
> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> @@ -637,6 +637,10 @@ static int a6xx_calc_ubwc_config(struct adreno_gpu *gpu)
> if (adreno_is_a702(gpu))
> cfg->highest_bank_bit = 14;
>
> + if (cfg->highest_bank_bit != common_cfg->highest_bank_bit)
> + DRM_WARN_ONCE("Inconclusive highest_bank_bit value: %u (GPU) vs %u (UBWC_CFG)\n",
> + cfg->highest_bank_bit, common_cfg->highest_bank_bit);
> +
This really should come in an earlier patch...
> gpu->ubwc_config = &gpu->_ubwc_config;
>
> return 0;
>
> --
> 2.49.0
>
--
With best wishes
Dmitry