Some GPUs - particularly A7xx ones - are really really stubborn and sometimes take a longer-than-expected time to finish unhalting GBIF. Note that this is not caused by the request a few lines above. Poll for the unhalt ack to make sure we're not trying to write bits to an essentially dead GPU that can't receive data on its end of the bus. Failing to do this will result in inexplicable GMU timeouts or worse. This is a rather ugly hack which introduces a whole lot of latency. Tested-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx> # on SM8550-QRD Tested-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> # sm8450 Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> --- 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 2313620084b6..11cb410e0ac7 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c @@ -1629,6 +1629,10 @@ static int hw_init(struct msm_gpu *gpu) mb(); } + /* Some GPUs are stubborn and take their sweet time to unhalt GBIF! */ + if (adreno_is_a7xx(adreno_gpu) && a6xx_has_gbif(adreno_gpu)) + spin_until(!gpu_read(gpu, REG_A6XX_GBIF_HALT_ACK)); + gpu_write(gpu, REG_A6XX_RBBM_SECVID_TSB_CNTL, 0); if (adreno_is_a619_holi(adreno_gpu)) -- 2.42.0
