From: houlong.wei <houlong.wei@mediatek.com> To: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>, <minghsiu.tsai@mediatek.com> Cc: <andrew-ct.chen@mediatek.com>, <mchehab@kernel.org>, <matthias.bgg@gmail.com>, <hans.verkuil@cisco.com>, <linux-media@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>, <linux-mediatek@lists.infradead.org>, <linux-kernel@vger.kernel.org>, <kernel@collabora.com>, <acourbot@chromium.org>, <irui.wang@mediatek.com>, <houlong.wei@mediatek.com> Subject: Re: [PATCH] media: platform: mtk-mdp: Fix mdp_ipi_comm structure alignment Date: Fri, 22 Apr 2022 10:51:02 +0800 [thread overview] Message-ID: <6ffdf93599e0b55bd3640ef3f17a9255635f0b79.camel@mediatek.com> (raw) In-Reply-To: <7658c8e4-596b-abfc-9255-854c16f920a7@collabora.com> On Thu, 2022-04-21 at 13:03 +0200, AngeloGioacchino Del Regno wrote: > Il 07/03/22 16:56, AngeloGioacchino Del Regno ha scritto: > > The mdp_ipi_comm structure defines a command that is either > > PROCESS (start processing) or DEINIT (destroy instance); we > > are using this one to send PROCESS or DEINIT commands from Linux > > to an MDP instance through a VPU write but, while the first wants > > us to stay 4-bytes aligned, the VPU instead requires an 8-bytes > > data alignment. > > > > Keeping in mind that these commands are executed immediately > > after sending them (hence not chained with others before the > > VPU/MDP "actually" start executing), it is fine to simply add > > a padding of 4 bytes to this structure: this keeps the same > > performance as before, as we're still stack-allocating it, > > while avoiding hackery inside of mtk-vpu to ensure alignment > > bringing a definitely bigger performance impact. > > > > Fixes: c8eb2d7e8202 ("[media] media: Add Mediatek MDP Driver") > > Signed-off-by: AngeloGioacchino Del Regno < > > angelogioacchino.delregno@collabora.com> > > Hello, > is there any issue with this patch? > > Regards, > Angelo > The 'padding' is added at the end of the struct, there will be no problem in the VPU firmware. Thanks for the patch. Reviewed-by: Houlong Wei <houlong.wei@mediatek.com> > > --- > > > > This patch has been tested on Acer Chromebook R 13 (MT8173 Elm) on > > Debian Sid. > > > > This is an alternative solution to the mtk-vpu approach, found > > here: > > https://lore.kernel.org/all/20210920170408.1561-1-dafna.hirschfeld@collabora.com > > > > drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h > > b/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h > > index 2cb8cecb3077..b810c96695c8 100644 > > --- a/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h > > +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h > > @@ -40,12 +40,14 @@ struct mdp_ipi_init { > > * @ipi_id : IPI_MDP > > * @ap_inst : AP mtk_mdp_vpu address > > * @vpu_inst_addr : VPU MDP instance address > > + * @padding : Alignment padding > > */ > > struct mdp_ipi_comm { > > uint32_t msg_id; > > uint32_t ipi_id; > > uint64_t ap_inst; > > uint32_t vpu_inst_addr; > > + uint32_t padding; > > }; > > > > /** > > _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek
WARNING: multiple messages have this Message-ID (diff)
From: houlong.wei <houlong.wei@mediatek.com> To: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>, <minghsiu.tsai@mediatek.com> Cc: <andrew-ct.chen@mediatek.com>, <mchehab@kernel.org>, <matthias.bgg@gmail.com>, <hans.verkuil@cisco.com>, <linux-media@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>, <linux-mediatek@lists.infradead.org>, <linux-kernel@vger.kernel.org>, <kernel@collabora.com>, <acourbot@chromium.org>, <irui.wang@mediatek.com>, <houlong.wei@mediatek.com> Subject: Re: [PATCH] media: platform: mtk-mdp: Fix mdp_ipi_comm structure alignment Date: Fri, 22 Apr 2022 10:51:02 +0800 [thread overview] Message-ID: <6ffdf93599e0b55bd3640ef3f17a9255635f0b79.camel@mediatek.com> (raw) In-Reply-To: <7658c8e4-596b-abfc-9255-854c16f920a7@collabora.com> On Thu, 2022-04-21 at 13:03 +0200, AngeloGioacchino Del Regno wrote: > Il 07/03/22 16:56, AngeloGioacchino Del Regno ha scritto: > > The mdp_ipi_comm structure defines a command that is either > > PROCESS (start processing) or DEINIT (destroy instance); we > > are using this one to send PROCESS or DEINIT commands from Linux > > to an MDP instance through a VPU write but, while the first wants > > us to stay 4-bytes aligned, the VPU instead requires an 8-bytes > > data alignment. > > > > Keeping in mind that these commands are executed immediately > > after sending them (hence not chained with others before the > > VPU/MDP "actually" start executing), it is fine to simply add > > a padding of 4 bytes to this structure: this keeps the same > > performance as before, as we're still stack-allocating it, > > while avoiding hackery inside of mtk-vpu to ensure alignment > > bringing a definitely bigger performance impact. > > > > Fixes: c8eb2d7e8202 ("[media] media: Add Mediatek MDP Driver") > > Signed-off-by: AngeloGioacchino Del Regno < > > angelogioacchino.delregno@collabora.com> > > Hello, > is there any issue with this patch? > > Regards, > Angelo > The 'padding' is added at the end of the struct, there will be no problem in the VPU firmware. Thanks for the patch. Reviewed-by: Houlong Wei <houlong.wei@mediatek.com> > > --- > > > > This patch has been tested on Acer Chromebook R 13 (MT8173 Elm) on > > Debian Sid. > > > > This is an alternative solution to the mtk-vpu approach, found > > here: > > https://lore.kernel.org/all/20210920170408.1561-1-dafna.hirschfeld@collabora.com > > > > drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h > > b/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h > > index 2cb8cecb3077..b810c96695c8 100644 > > --- a/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h > > +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h > > @@ -40,12 +40,14 @@ struct mdp_ipi_init { > > * @ipi_id : IPI_MDP > > * @ap_inst : AP mtk_mdp_vpu address > > * @vpu_inst_addr : VPU MDP instance address > > + * @padding : Alignment padding > > */ > > struct mdp_ipi_comm { > > uint32_t msg_id; > > uint32_t ipi_id; > > uint64_t ap_inst; > > uint32_t vpu_inst_addr; > > + uint32_t padding; > > }; > > > > /** > > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-04-22 2:51 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-03-07 15:56 [PATCH] media: platform: mtk-mdp: Fix mdp_ipi_comm structure alignment AngeloGioacchino Del Regno 2022-03-07 15:56 ` AngeloGioacchino Del Regno 2022-03-07 15:56 ` AngeloGioacchino Del Regno 2022-04-21 11:03 ` AngeloGioacchino Del Regno 2022-04-21 11:03 ` AngeloGioacchino Del Regno 2022-04-21 11:03 ` AngeloGioacchino Del Regno 2022-04-22 2:51 ` houlong.wei [this message] 2022-04-22 2:51 ` houlong.wei 2022-04-22 2:52 ` Irui Wang 2022-04-22 2:52 ` Irui Wang 2022-04-22 2:52 ` Irui Wang
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