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Wed, 28 Apr 2021 02:45:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id AF33661422; Wed, 28 Apr 2021 06:44:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1619592277; bh=S5Mcku9BqGbqEVzg3DUAzz6HUqoWQEP/3bQrKYHAHMc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=r9ycOZc92ZLGH/GJuCv8MF7WWLmvTEaREagiqxoz+xK7lS7SbaUOHTzN1PMuj8UjJ QWyI3+JkOZA8z6EGW4Xme+vGCTDqcmo8OO3306UV3aURYRQfW8z9n1Tzk2keHc64cr IW0HJL4lG2zKVRksW0AYgU+vUWvmgLgnqR1U34mPnXxf5bZOWnbqKvibhO4rFeW37+ i7RHXl9HsZxwdH3hCS2lrTprfoZ5B2YkeM3E/1oDy+JQsJ7ahj5CXImovf4/Ev87eF 5dZUBedqinMq/KJ+5wDpfTmXenF6H8psD75QQq4WY4FpCXiL11BTb+jkI422CRl7hh HUMdUbdPFl1wg== Date: Wed, 28 Apr 2021 08:44:31 +0200 From: Mauro Carvalho Chehab To: Ezequiel Garcia Cc: Robin Murphy , linuxarm@huawei.com, mauro.chehab@huawei.com, Greg Kroah-Hartman , Mauro Carvalho Chehab , Philipp Zabel , devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org Subject: Re: [PATCH v3 79/79] media: hantro: document the usage of pm_runtime_get_sync() Message-ID: <20210428084431.0c2d505b@coco.lan> In-Reply-To: <20210428082742.20d54db1@coco.lan> References: <230f22170db7fa57b49cff4570cef15bf11b2ad5.1619519080.git.mchehab+huawei@kernel.org> <02948673-9572-a570-d28e-03a7208f39e1@arm.com> <95ea572e201545b27ff9f48313f7aaea157d4764.camel@collabora.com> <20210428082742.20d54db1@coco.lan> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Em Wed, 28 Apr 2021 08:27:42 +0200 Mauro Carvalho Chehab escreveu: > Em Tue, 27 Apr 2021 12:18:32 -0300 > Ezequiel Garcia escreveu: >=20 > > On Tue, 2021-04-27 at 16:08 +0100, Robin Murphy wrote: =20 > > > On 2021-04-27 11:27, Mauro Carvalho Chehab wrote: =20 > > > > Despite other *_get()/*_put() functions, where usage count is > > > > incremented only if not errors, the pm_runtime_get_sync() has > > > > a different behavior, incrementing the counter *even* on > > > > errors. > > > >=20 > > > > That's an error prone behavior, as people often forget to > > > > decrement the usage counter. > > > >=20 > > > > However, the hantro driver depends on this behavior, as it > > > > will decrement the usage_count unconditionally at the m2m > > > > job finish time, which makes sense. > > > >=20 > > > > So, intead of using the pm_runtime_resume_and_get() that > > > > would decrement the counter on error, keep the current > > > > API, but add a documentation explaining the rationale for > > > > keep using pm_runtime_get_sync(). > > > >=20 > > > > Signed-off-by: Mauro Carvalho Chehab > > > > --- > > > > =C2=A0 drivers/staging/media/hantro/hantro_drv.c | 7 +++++++ > > > > =C2=A0 1 file changed, 7 insertions(+) > > > >=20 > > > > diff --git a/drivers/staging/media/hantro/hantro_drv.c b/drivers/st= aging/media/hantro/hantro_drv.c > > > > index 595e82a82728..96f940c1c85c 100644 > > > > --- a/drivers/staging/media/hantro/hantro_drv.c > > > > +++ b/drivers/staging/media/hantro/hantro_drv.c > > > > @@ -155,6 +155,13 @@ static void device_run(void *priv) > > > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0ret =3D clk_bulk_en= able(ctx->dev->variant->num_clocks, ctx->dev->clocks); > > > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (ret) > > > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0goto err_cancel_job; =20 > > >=20 > > > ..except this can also cause the same pm_runtime_put_autosuspend() ca= ll=20 > > > without even reaching the "matching" get below, so rather than some k= ind=20 > > > of cleverness it seems more like it's just broken :/ > > > =20 > >=20 > > Indeed, I was trying to find time to cook a quick patch, but kept > > getting preempted. > >=20 > > Feel free to submit a fix for this, otherwise, I'll try to find > > time later this week. =20 >=20 > What about doing this instead: >=20 > diff --git a/drivers/staging/media/hantro/hantro_drv.c b/drivers/staging/= media/hantro/hantro_drv.c > index 595e82a82728..67de6b15236d 100644 > --- a/drivers/staging/media/hantro/hantro_drv.c > +++ b/drivers/staging/media/hantro/hantro_drv.c > @@ -56,14 +56,12 @@ dma_addr_t hantro_get_ref(struct hantro_ctx *ctx, u64= ts) > return hantro_get_dec_buf_addr(ctx, buf); > } > =20 > -static void hantro_job_finish(struct hantro_dev *vpu, > - struct hantro_ctx *ctx, > - enum vb2_buffer_state result) > +static void hantro_job_finish_no_pm(struct hantro_dev *vpu, > + struct hantro_ctx *ctx, > + enum vb2_buffer_state result) > { > struct vb2_v4l2_buffer *src, *dst; > =20 > - pm_runtime_mark_last_busy(vpu->dev); > - pm_runtime_put_autosuspend(vpu->dev); > clk_bulk_disable(vpu->variant->num_clocks, vpu->clocks); > =20 > src =3D v4l2_m2m_next_src_buf(ctx->fh.m2m_ctx); > @@ -81,6 +79,16 @@ static void hantro_job_finish(struct hantro_dev *vpu, > result); > } > =20 > +static void hantro_job_finish(struct hantro_dev *vpu, > + struct hantro_ctx *ctx, > + enum vb2_buffer_state result) > +{ > + pm_runtime_mark_last_busy(vpu->dev); > + pm_runtime_put_autosuspend(vpu->dev); > + > + hantro_job_finish_no_pm(vpu, ctx, result); > +} > + > void hantro_irq_done(struct hantro_dev *vpu, > enum vb2_buffer_state result) > { > @@ -152,12 +160,13 @@ static void device_run(void *priv) > src =3D hantro_get_src_buf(ctx); > dst =3D hantro_get_dst_buf(ctx); > =20 > + ret =3D pm_runtime_resume_and_get(ctx->dev->dev); > + if (ret < 0) > + goto err_cancel_job; > + > ret =3D clk_bulk_enable(ctx->dev->variant->num_clocks, ctx->dev->clocks= ); > if (ret) > goto err_cancel_job; > - ret =3D pm_runtime_get_sync(ctx->dev->dev); > - if (ret < 0) > - goto err_cancel_job; > =20 > v4l2_m2m_buf_copy_metadata(src, dst, true); > =20 > @@ -165,7 +174,7 @@ static void device_run(void *priv) > return; > =20 > err_cancel_job: > - hantro_job_finish(ctx->dev, ctx, VB2_BUF_STATE_ERROR); > + hantro_job_finish_no_pm(ctx->dev, ctx, VB2_BUF_STATE_ERROR); > } > =20 > static struct v4l2_m2m_ops vpu_m2m_ops =3D { >=20 > Thanks, > Mauro Actually, the order at the finish logic should change as well. Maybe like this: static void hantro_job_finish_no_pm(struct hantro_dev *vpu, struct hantro_ctx *ctx, enum vb2_buffer_state result) { struct vb2_v4l2_buffer *src, *dst; src =3D v4l2_m2m_next_src_buf(ctx->fh.m2m_ctx); dst =3D v4l2_m2m_next_dst_buf(ctx->fh.m2m_ctx); if (WARN_ON(!src)) return; if (WARN_ON(!dst)) return; src->sequence =3D ctx->sequence_out++; dst->sequence =3D ctx->sequence_cap++; v4l2_m2m_buf_done_and_job_finish(ctx->dev->m2m_dev, ctx->fh.m2m_ctx, result); } static void hantro_job_finish(struct hantro_dev *vpu, struct hantro_ctx *ctx, enum vb2_buffer_state result) { hantro_job_finish_no_pm(vpu, ctx, result); clk_bulk_disable(vpu->variant->num_clocks, vpu->clocks); pm_runtime_mark_last_busy(vpu->dev); pm_runtime_put_autosuspend(vpu->dev); } static void device_run(void *priv) { struct hantro_ctx *ctx =3D priv; struct vb2_v4l2_buffer *src, *dst; int ret; src =3D hantro_get_src_buf(ctx); dst =3D hantro_get_dst_buf(ctx); ret =3D pm_runtime_resume_and_get(ctx->dev->dev); if (ret < 0) goto err_cancel_job; ret =3D clk_bulk_enable(ctx->dev->variant->num_clocks, ctx->dev->clocks); if (ret) goto err_cancel_job; v4l2_m2m_buf_copy_metadata(src, dst, true); ctx->codec_ops->run(ctx); return; err_cancel_job: hantro_job_finish_no_pm(ctx->dev, ctx, VB2_BUF_STATE_ERROR); } Thanks, Mauro