From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4F2BCC433B4 for ; Wed, 28 Apr 2021 06:27:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1257761421 for ; Wed, 28 Apr 2021 06:27:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235087AbhD1G2d (ORCPT ); Wed, 28 Apr 2021 02:28:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:38144 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232966AbhD1G2c (ORCPT ); Wed, 28 Apr 2021 02:28:32 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 873AB61158; Wed, 28 Apr 2021 06:27:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1619591268; bh=0XZAnGMbHQVb6640NACUhIc6RdCMbx/GXT7x2D/JQy8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=TTNCRtbSwT/1sPcCsPNBGMdt1T+unT0fTEBc7xEEJNuRXDHXQ6Yr3m3rCWgPfygv2 wpZyYjGW1b6saQCMxu2r7f633/udi8Y1TyYNlDM2dMyIx4KgYLng/im0COlcu2R2/j C+p7XV+6uorxR7fkT8FieAn7dvmh7yCgrQU4PPbEQpO8+PwNnB+c7NbxtpAs9JZGgj LRDnsoHpLcfUDUJ112FRCdmoutrb8+QWuO1n9LIH1IyVprMi8W8Gm7y9eVggDj3Hy0 Zc6K4hC03OHQu5qwRTwHs9TRjHtSk6PDlRyjMWwzT99e86p+8P689Ag+UrAFH4Qffa m1Oo9fuP0eVuw== Date: Wed, 28 Apr 2021 08:27:42 +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: <20210428082742.20d54db1@coco.lan> In-Reply-To: <95ea572e201545b27ff9f48313f7aaea157d4764.camel@collabora.com> References: <230f22170db7fa57b49cff4570cef15bf11b2ad5.1619519080.git.mchehab+huawei@kernel.org> <02948673-9572-a570-d28e-03a7208f39e1@arm.com> <95ea572e201545b27ff9f48313f7aaea157d4764.camel@collabora.com> 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 Tue, 27 Apr 2021 12:18:32 -0300 Ezequiel Garcia escreveu: > On Tue, 2021-04-27 at 16:08 +0100, Robin Murphy wrote: > > 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/stag= ing/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_enab= le(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() call= =20 > > without even reaching the "matching" get below, so rather than some kin= d=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. What about doing this instead: diff --git a/drivers/staging/media/hantro/hantro_drv.c b/drivers/staging/me= dia/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 t= s) 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 { Thanks, Mauro