<pre>
Hi CK,

Thanks for the reviews.

On Mon, 2023-06-12 at 09:05 +0000, CK Hu (胡俊光) wrote:
> Hi, Jason:
>
> On Fri, 2023-04-07 at 14:46 +0800, Jason-JH.Lin wrote:
> > Add casting before assign to avoid the unintentional integer
> > overflow
> > or unintended sign extension.
> >
> > Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
> > Fixes: 1a64a7aff8da ("drm/mediatek: Fix cursor plane no update")
> > ---
> > drivers/gpu/drm/mediatek/mtk_drm_gem.c | 2 +-
> > drivers/gpu/drm/mediatek/mtk_drm_plane.c | 20 +++++++++++---------
> > 2 files changed, 12 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_gem.c
> > b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
> > index 9b8f72ed12e4..537e83b95001 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_gem.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
> > @@ -121,7 +121,7 @@ int mtk_drm_gem_dumb_create(struct drm_file
> > *file_priv, struct drm_device *dev,
> > int ret;
> >
> > args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
> > -args->size = args->pitch * args->height;
> > +args->size = (unsigned long)args->pitch * args->height;
>
> The prototype is
>
> struct drm_mode_create_dump {
> __u32 height;
> __u32 pitch;
> __u64 size;
> };
>
> Do you want to case to "__u64"?
>
Yes, it should be (unsigned long long), but I'll change it to:
args->size = (__u64)args->pitch * args->height;

> >
> > mtk_gem = mtk_drm_gem_create(dev, args->size, false);
> > if (IS_ERR(mtk_gem))
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_plane.c
> > b/drivers/gpu/drm/mediatek/mtk_drm_plane.c
> > index 31f9420aff6f..a1337f386bbf 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_plane.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_plane.c
> > @@ -140,7 +140,7 @@ static void mtk_plane_update_new_state(struct
> > drm_plane_state *new_state,
> > struct drm_framebuffer *fb = new_state->fb;
> > struct drm_gem_object *gem;
> > struct mtk_drm_gem_obj *mtk_gem;
> > -unsigned int pitch, format;
> > +unsigned int pitch, format, cpp;
> > u64 modifier;
> > dma_addr_t addr;
> > dma_addr_t hdr_addr = 0;
> > @@ -151,11 +151,12 @@ static void mtk_plane_update_new_state(struct
> > drm_plane_state *new_state,
> > addr = mtk_gem->dma_addr;
> > pitch = fb->pitches[0];
> > format = fb->format->format;
> > +cpp = (unsigned int)fb->format->cpp[0];
> > modifier = fb->modifier;
> >
> > if (modifier == DRM_FORMAT_MOD_LINEAR) {
> > -addr += (new_state->src.x1 >> 16) * fb->format->cpp[0];
> > -addr += (new_state->src.y1 >> 16) * pitch;
> > +addr += (dma_addr_t)(new_state->src.x1 >> 16) * cpp;
> > +addr += (dma_addr_t)(new_state->src.y1 >> 16) * pitch;
> > } else {
> > int width_in_blocks = ALIGN(fb->width,
> > AFBC_DATA_BLOCK_WIDTH)
> > / AFBC_DATA_BLOCK_WIDTH;
> > @@ -167,17 +168,18 @@ static void mtk_plane_update_new_state(struct
> > drm_plane_state *new_state,
> >
> > hdr_pitch = width_in_blocks * AFBC_HEADER_BLOCK_SIZE;
> > pitch = width_in_blocks * AFBC_DATA_BLOCK_WIDTH *
> > -AFBC_DATA_BLOCK_HEIGHT * fb->format->cpp[0];
> > +AFBC_DATA_BLOCK_HEIGHT * cpp;
> >
> > hdr_size = ALIGN(hdr_pitch * height_in_blocks,
> > AFBC_HEADER_ALIGNMENT);
> >
> > -hdr_addr = addr + hdr_pitch * y_offset_in_blocks +
> > - AFBC_HEADER_BLOCK_SIZE * x_offset_in_blocks;
> > +hdr_addr = addr +
> > + (dma_addr_t)hdr_pitch * y_offset_in_blocks +
> > + (dma_addr_t)AFBC_HEADER_BLOCK_SIZE *
> > x_offset_in_blocks;
> > /* The data plane is offset by 1 additional block. */
> > addr = addr + hdr_size +
> > - pitch * y_offset_in_blocks +
> > - AFBC_DATA_BLOCK_WIDTH * AFBC_DATA_BLOCK_HEIGHT *
> > - fb->format->cpp[0] * (x_offset_in_blocks + 1);
> > + (dma_addr_t)pitch * y_offset_in_blocks +
> > + (dma_addr_t)AFBC_DATA_BLOCK_WIDTH *
> > AFBC_DATA_BLOCK_HEIGHT *
> > + (dma_addr_t)cpp * (x_offset_in_blocks + 1);
> > }
>
> I would like you to add a variable 'u32 offset' for this calculating,
> and I think u32 is enough for this calculating and it's not necessary
> to do any casting.
>
> Regards,
> CK

I think x_offset_in_blocks and y_offset_in_blocks may be negative,
so I'll use 'int offset' for this calculating.

Regards,
Jason-JH.Lin

>
> >
> > mtk_plane_state->pending.enable = true;

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