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[83.9.30.82]) by smtp.gmail.com with ESMTPSA id m25-20020a056512015900b004fb86c89fa1sm753363lfo.135.2023.06.28.13.35.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Jun 2023 13:35:46 -0700 (PDT) From: Konrad Dybcio Date: Wed, 28 Jun 2023 22:35:14 +0200 Subject: [PATCH RFC 14/14] drm/msm/a6xx: Poll for GBIF unhalt status in hw_init MIME-Version: 1.0 Message-Id: <20230628-topic-a7xx_drmmsm-v1-14-a7f4496e0c12@linaro.org> References: <20230628-topic-a7xx_drmmsm-v1-0-a7f4496e0c12@linaro.org> In-Reply-To: <20230628-topic-a7xx_drmmsm-v1-0-a7f4496e0c12@linaro.org> To: Rob Clark , Abhinav Kumar , Dmitry Baryshkov , Sean Paul , David Airlie , Daniel Vetter , Rob Herring , Krzysztof Kozlowski , Conor Dooley Cc: Marijn Suijten , linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Konrad Dybcio X-Mailer: b4 0.12.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1687984524; l=1255; i=konrad.dybcio@linaro.org; s=20230215; h=from:subject:message-id; bh=5Q1kvDGqQf+MZGSOe2N8n59sdYSKweQE1iz0+XOB04c=; b=eXvXP/e+RhlAwoWIAvEi5snC/1AjilAjPzcIT9/z050IFx7BiJqsJPVjijWMHbh0Eosacg1Mh yHlbBK/Mq2rB0sbPFYndGRfJjM8/YkKiNuzpi1B5hPjhfx845Uzw/Wt X-Developer-Key: i=konrad.dybcio@linaro.org; a=ed25519; pk=iclgkYvtl2w05SSXO5EjjSYlhFKsJ+5OSZBjOkQuEms= Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org 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. Signed-off-by: Konrad Dybcio --- 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 fac325217a7e..b0fa764ba299 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))