RE: [PATCH] media: s5p-mfc: Corrected NV12M/NV21M plane-sizes

["Aakarsh Jain" <aakarsh.jain@samsung.com>]

> -----Original Message-----
> From: Aakarsh Jain <aakarsh.jain@samsung.com>
> Sent: 07 August 2024 17:23
> To: 'Nicolas Dufresne' <nicolas@ndufresne.ca>; 'linux-arm-
> kernel@lists.infradead.org' <linux-arm-kernel@lists.infradead.org>; 'linux-
> media@vger.kernel.org' <linux-media@vger.kernel.org>; 'linux-
> kernel@vger.kernel.org' <linux-kernel@vger.kernel.org>
> Cc: 'm.szyprowski@samsung.com' <m.szyprowski@samsung.com>;
> 'andrzej.hajda@intel.com' <andrzej.hajda@intel.com>;
> 'mchehab@kernel.org' <mchehab@kernel.org>; 'hverkuil-cisco@xs4all.nl'
> <hverkuil-cisco@xs4all.nl>; 'krzysztof.kozlowski+dt@linaro.org'
> <krzysztof.kozlowski+dt@linaro.org>; 'linux-samsung-soc@vger.kernel.org'
> <linux-samsung-soc@vger.kernel.org>; 'gost.dev@samsung.com'
> <gost.dev@samsung.com>; 'aswani.reddy@samsung.com'
> <aswani.reddy@samsung.com>; 'pankaj.dubey@samsung.com'
> <pankaj.dubey@samsung.com>
> Subject: RE: [PATCH] media: s5p-mfc: Corrected NV12M/NV21M plane-sizes
> 
> Hi Nocolas,
> 
> > -----Original Message-----
> > From: Nicolas Dufresne <nicolas@ndufresne.ca>
> > Sent: 06 August 2024 20:08
> > To: Aakarsh Jain <aakarsh.jain@samsung.com>; linux-arm-
> > kernel@lists.infradead.org; linux-media@vger.kernel.org; linux-
> > kernel@vger.kernel.org
> > Cc: m.szyprowski@samsung.com; andrzej.hajda@intel.com;
> > mchehab@kernel.org; hverkuil-cisco@xs4all.nl;
> > krzysztof.kozlowski+dt@linaro.org; linux-samsung-soc@vger.kernel.org;
> > gost.dev@samsung.com; aswani.reddy@samsung.com;
> > pankaj.dubey@samsung.com
> > Subject: Re: [PATCH] media: s5p-mfc: Corrected NV12M/NV21M plane-
> sizes
> >
> > Hi Jain,
> >
> > I haven't dig much, but I have a quick question below.
> >
> > Le mardi 06 août 2024 à 17:27 +0530, Aakarsh Jain a écrit :
> > > There is a possibility of getting page fault if the overall buffer
> > > size is not aligned to 256bytes. Since MFC does read operation only
> > > and it won't corrupt the data values even if it reads the extra bytes.
> > > Corrected luma and chroma plane sizes for V4L2_PIX_FMT_NV12M and
> > > V4L2_PIX_FMT_NV21M pixel format.
> >
> > Have you re-run v4l2 compliance ? (better be safe then sorry).
> >
> I ran v4l2-compliance and didn't found any issue wrt to the changes added in
> this patch.
> Please find the v4l2-compliance report attached.
> 
> > >
> > > Signed-off-by: Aakarsh Jain <aakarsh.jain@samsung.com>
> > > ---
> > >  .../media/platform/samsung/s5p-mfc/s5p_mfc_opr_v6.c    | 10 ++++++-
> ---
> > >  1 file changed, 6 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/media/platform/samsung/s5p-mfc/s5p_mfc_opr_v6.c
> > > b/drivers/media/platform/samsung/s5p-mfc/s5p_mfc_opr_v6.c
> > > index 73f7af674c01..03c957221fc4 100644
> > > --- a/drivers/media/platform/samsung/s5p-mfc/s5p_mfc_opr_v6.c
> > > +++ b/drivers/media/platform/samsung/s5p-mfc/s5p_mfc_opr_v6.c
> > > @@ -498,8 +498,8 @@ static void s5p_mfc_dec_calc_dpb_size_v6(struct
> > s5p_mfc_ctx *ctx)
> > >  	case V4L2_PIX_FMT_NV21M:
> > >  		ctx->stride[0] = ALIGN(ctx->img_width,
> > S5P_FIMV_NV12MT_HALIGN_V6);
> > >  		ctx->stride[1] = ALIGN(ctx->img_width,
> > S5P_FIMV_NV12MT_HALIGN_V6);
> > > -		ctx->luma_size = calc_plane(ctx->stride[0], ctx->img_height);
> > > -		ctx->chroma_size = calc_plane(ctx->stride[1], (ctx-
> > >img_height / 2));
> > > +		ctx->luma_size = calc_plane(ctx->img_width, ctx-
> > >img_height);
> > > +		ctx->chroma_size = calc_plane(ctx->img_width, (ctx-
> > >img_height >>
> > > +1));
> >
> > These size needs to match the sizes reported through TRY_FMT (and
> > S_FMT) sizeimage for each planes. Is this code being call withing
> > try_fmt ? Will these value match or will this change cause the value to miss-
> match ?
> >
> This code is getting called within try_fmt. In MFC driver we are not returning
> any sizes in TRY_FMT. We are only validating codec and the pixel format. We
> are setting luma, chroma and stride size in S_FMT to inform user space for
> further buffer allocation. So, this change is not going to cause any mismatch.
> 
> > The reason is that correct value is needed for allocating this memory
> > from the outside (like using a DMAbuf Heap). Perhaps its all right, let me
> know.
> >
> > Nicolas
> >
> > >  		break;
> > >  	case V4L2_PIX_FMT_YUV420M:
> > >  	case V4L2_PIX_FMT_YVU420M:
> > > @@ -539,9 +539,11 @@ static void
> s5p_mfc_dec_calc_dpb_size_v6(struct
> > > s5p_mfc_ctx *ctx)  static void s5p_mfc_enc_calc_src_size_v6(struct
> > > s5p_mfc_ctx *ctx)  {
> > >  	unsigned int mb_width, mb_height;
> > > +	unsigned int default_size;
> > >
> > >  	mb_width = MB_WIDTH(ctx->img_width);
> > >  	mb_height = MB_HEIGHT(ctx->img_height);
> > > +	default_size = (mb_width * mb_height) * 256;
> > >
> > >  	if (IS_MFCV12(ctx->dev)) {
> > >  		switch (ctx->src_fmt->fourcc) {
> > > @@ -549,8 +551,8 @@ static void s5p_mfc_enc_calc_src_size_v6(struct
> > s5p_mfc_ctx *ctx)
> > >  		case V4L2_PIX_FMT_NV21M:
> > >  			ctx->stride[0] = ALIGN(ctx->img_width,
> > S5P_FIMV_NV12M_HALIGN_V6);
> > >  			ctx->stride[1] = ALIGN(ctx->img_width,
> > S5P_FIMV_NV12M_HALIGN_V6);
> > > -			ctx->luma_size = ctx->stride[0] * ALIGN(ctx-
> > >img_height, 16);
> > > -			ctx->chroma_size =  ctx->stride[0] * ALIGN(ctx-
> > >img_height / 2, 16);
> > > +			ctx->luma_size = ALIGN(default_size, 256);
> > > +			ctx->chroma_size = ALIGN(default_size / 2, 256);
> > >  			break;
> > >  		case V4L2_PIX_FMT_YUV420M:
> > >  		case V4L2_PIX_FMT_YVU420M:

Gentle reminder to review this patch.