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[188.141.3.169]) by smtp.gmail.com with ESMTPSA id y12-20020adfee0c000000b0031aeca90e1fsm12873690wrn.70.2023.08.22.13.06.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Aug 2023 13:06:34 -0700 (PDT) From: Bryan O'Donoghue To: rfoss@kernel.org, todor.too@gmail.com, bryan.odonoghue@linaro.org, agross@kernel.org, andersson@kernel.org, konrad.dybcio@linaro.org, mchehab@kernel.org, hverkuil-cisco@xs4all.nl, laurent.pinchart@ideasonboard.com, sakari.ailus@linux.intel.com, andrey.konovalov@linaro.org Cc: linux-media@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v2 4/9] media: qcom: camss: Fix VFE-17x vfe_disable_output() Date: Tue, 22 Aug 2023 21:06:21 +0100 Message-ID: <20230822200626.1931129-5-bryan.odonoghue@linaro.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230822200626.1931129-1-bryan.odonoghue@linaro.org> References: <20230822200626.1931129-1-bryan.odonoghue@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" There are two problems with the current vfe_disable_output() routine. Firstly we rightly use a spinlock to protect output->gen2.active_num everywhere except for in the IDLE timeout path of vfe_disable_output(). Even if that is not racy "in practice" somehow it is by happenstance not by design. Secondly we do not get consistent behaviour from this routine. On sc8280xp 50% of the time I get "VFE idle timeout - resetting". In this case the subsequent capture will succeed. The other 50% of the time, we don't hit the idle timeout, never do the VFE reset and subsequent captures stall indefinitely. Rewrite the vfe_disable_output() routine to - Quiesce write masters with vfe_wm_stop() - Set active_num =3D 0 remembering to hold the spinlock when we do so followed by - Reset the VFE Testing on sc8280xp and sdm845 shows this to be a valid fix. Fixes: 7319cdf189bb ("media: camss: Add support for VFE hardware version Ti= tan 170") Cc: stable@vger.kernel.org Signed-off-by: Bryan O'Donoghue --- .../media/platform/qcom/camss/camss-vfe-170.c | 19 +++---------------- 1 file changed, 3 insertions(+), 16 deletions(-) diff --git a/drivers/media/platform/qcom/camss/camss-vfe-170.c b/drivers/me= dia/platform/qcom/camss/camss-vfe-170.c index 02494c89da91c..ae9137633c301 100644 --- a/drivers/media/platform/qcom/camss/camss-vfe-170.c +++ b/drivers/media/platform/qcom/camss/camss-vfe-170.c @@ -500,28 +500,15 @@ static int vfe_disable_output(struct vfe_line *line) struct vfe_output *output =3D &line->output; unsigned long flags; unsigned int i; - bool done; - int timeout =3D 0; - - do { - spin_lock_irqsave(&vfe->output_lock, flags); - done =3D !output->gen2.active_num; - spin_unlock_irqrestore(&vfe->output_lock, flags); - usleep_range(10000, 20000); - - if (timeout++ =3D=3D 100) { - dev_err(vfe->camss->dev, "VFE idle timeout - resetting\n"); - vfe_reset(vfe); - output->gen2.active_num =3D 0; - return 0; - } - } while (!done); =20 spin_lock_irqsave(&vfe->output_lock, flags); for (i =3D 0; i < output->wm_num; i++) vfe_wm_stop(vfe, output->wm_idx[i]); + output->gen2.active_num =3D 0; spin_unlock_irqrestore(&vfe->output_lock, flags); =20 + vfe_reset(vfe); + return 0; } =20 --=20 2.41.0