Re: [PATCH v2 3/9] drm/format-helper: Add destination-buffer pitch to drm_fb_swab()

["Amanoel Dawod" <kernel@amanoeldawod.com>]

Hi,

On Mon, Nov 1, 2021, at 10:15 AM, Thomas Zimmermann wrote:
> Add destination-buffer pitch as argument to drm_fb_swab(). Done for
> consistency with the rest of the interface.
>
> v2:
> 	* update documentation (Noralf)
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Tested-by: Noralf Trønnes <noralf@tronnes.org>
> Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
> ---
>  drivers/gpu/drm/drm_format_helper.c | 21 ++++++++++++++++-----
>  drivers/gpu/drm/drm_mipi_dbi.c      |  2 +-
>  drivers/gpu/drm/gud/gud_pipe.c      |  2 +-
>  include/drm/drm_format_helper.h     |  5 +++--
>  4 files changed, 21 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_format_helper.c 
> b/drivers/gpu/drm/drm_format_helper.c
> index fac37c697d8b..dac355320287 100644
> --- a/drivers/gpu/drm/drm_format_helper.c
> +++ b/drivers/gpu/drm/drm_format_helper.c
> @@ -101,6 +101,7 @@ EXPORT_SYMBOL(drm_fb_memcpy_toio);
>  /**
>   * drm_fb_swab - Swap bytes into clip buffer
>   * @dst: Destination buffer
> + * @dst_pitch: Number of bytes between two consecutive scanlines 
> within dst
>   * @src: Source buffer
>   * @fb: DRM framebuffer
>   * @clip: Clip rectangle area to copy
> @@ -110,21 +111,27 @@ EXPORT_SYMBOL(drm_fb_memcpy_toio);
>   * time to speed up slow uncached reads.
>   *
>   * This function does not apply clipping on dst, i.e. the destination
> - * is a small buffer containing the clip rect only.
> + * is at the top-left corner.
>   */
> -void drm_fb_swab(void *dst, void *src, struct drm_framebuffer *fb,
> -		 struct drm_rect *clip, bool cached)
> +void drm_fb_swab(void *dst, unsigned int dst_pitch, const void *src,
> +		 const struct drm_framebuffer *fb, const struct drm_rect *clip,
> +		 bool cached)
>  {
>  	u8 cpp = fb->format->cpp[0];
>  	size_t len = drm_rect_width(clip) * cpp;
> -	u16 *src16, *dst16 = dst;
> -	u32 *src32, *dst32 = dst;
> +	const u16 *src16;
> +	const u32 *src32;
> +	u16 *dst16;
> +	u32 *dst32;
>  	unsigned int x, y;
>  	void *buf = NULL;
> 
>  	if (WARN_ON_ONCE(cpp != 2 && cpp != 4))
>  		return;
> 
> +	if (!dst_pitch)
> +		dst_pitch = len;
> +
>  	if (!cached)
>  		buf = kmalloc(len, GFP_KERNEL);
> 
> @@ -140,6 +147,9 @@ void drm_fb_swab(void *dst, void *src, struct 
> drm_framebuffer *fb,
>  			src32 = src;
>  		}
> 
> +		dst16 = dst;
> +		dst32 = dst;
> +
>  		for (x = clip->x1; x < clip->x2; x++) {
>  			if (cpp == 4)
>  				*dst32++ = swab32(*src32++);
> @@ -148,6 +158,7 @@ void drm_fb_swab(void *dst, void *src, struct 
> drm_framebuffer *fb,
>  		}
> 
>  		src += fb->pitches[0];
> +		dst += dst_pitch;
>  	}
> 
>  	kfree(buf);
> diff --git a/drivers/gpu/drm/drm_mipi_dbi.c 
> b/drivers/gpu/drm/drm_mipi_dbi.c
> index c09df8b06c7a..7ce89917d761 100644
> --- a/drivers/gpu/drm/drm_mipi_dbi.c
> +++ b/drivers/gpu/drm/drm_mipi_dbi.c
> @@ -211,7 +211,7 @@ int mipi_dbi_buf_copy(void *dst, struct 
> drm_framebuffer *fb,
>  	switch (fb->format->format) {
>  	case DRM_FORMAT_RGB565:
>  		if (swap)
> -			drm_fb_swab(dst, src, fb, clip, !gem->import_attach);
> +			drm_fb_swab(dst, 0, src, fb, clip, !gem->import_attach);
>  		else
>  			drm_fb_memcpy(dst, 0, src, fb, clip);
>  		break;
> diff --git a/drivers/gpu/drm/gud/gud_pipe.c 
> b/drivers/gpu/drm/gud/gud_pipe.c
> index a92112ffd37a..e0b117b2559f 100644
> --- a/drivers/gpu/drm/gud/gud_pipe.c
> +++ b/drivers/gpu/drm/gud/gud_pipe.c
> @@ -201,7 +201,7 @@ static int gud_prep_flush(struct gud_device *gdrm, 
> struct drm_framebuffer *fb,
>  			len = gud_xrgb8888_to_color(buf, format, vaddr, fb, rect);
>  		}
>  	} else if (gud_is_big_endian() && format->cpp[0] > 1) {
> -		drm_fb_swab(buf, vaddr, fb, rect, !import_attach);
> +		drm_fb_swab(buf, 0, vaddr, fb, rect, !import_attach);
>  	} else if (compression && !import_attach && pitch == fb->pitches[0]) {
>  		/* can compress directly from the framebuffer */
>  		buf = vaddr + rect->y1 * pitch;
> diff --git a/include/drm/drm_format_helper.h 
> b/include/drm/drm_format_helper.h
> index 1fc3ba7b6060..ddcba5abe306 100644
> --- a/include/drm/drm_format_helper.h
> +++ b/include/drm/drm_format_helper.h
> @@ -17,8 +17,9 @@ void drm_fb_memcpy(void *dst, unsigned int dst_pitch, 
> const void *vaddr,
>  		   const struct drm_framebuffer *fb, const struct drm_rect *clip);
>  void drm_fb_memcpy_toio(void __iomem *dst, unsigned int dst_pitch, 
> const void *vaddr,
>  			const struct drm_framebuffer *fb, const struct drm_rect *clip);
> -void drm_fb_swab(void *dst, void *src, struct drm_framebuffer *fb,
> -		 struct drm_rect *clip, bool cached);
> +void drm_fb_swab(void *dst, unsigned int dst_pitch, const void *src,
> +		 const struct drm_framebuffer *fb, const struct drm_rect *clip,
> +		 bool cached);
>  void drm_fb_xrgb8888_to_rgb332(void *dst, void *vaddr, struct 
> drm_framebuffer *fb,
>  			       struct drm_rect *clip);
>  void drm_fb_xrgb8888_to_rgb565(void *dst, void *vaddr,
> -- 
> 2.33.1

Applying this fails for me (tested against 5.14 and 5.15 trees).
Example:
patching file include/drm/drm_format_helper.h
Hunk #1 FAILED at 17.

-- 
thanks,
Amanoel