Commit 2a81dba4 authored by Thomas Zimmermann's avatar Thomas Zimmermann Committed by Dave Airlie
Browse files

fbdev: Fix cfb_imageblit() for arbitrary image widths 



Commit 0d030118 ("fbdev: Improve performance of cfb_imageblit()")
broke cfb_imageblit() for image widths that are not aligned to 8-bit
boundaries. Fix this by handling the trailing pixels on each line
separately. The performance improvements in the original commit do not
regress by this change.

Signed-off-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Fixes: 0d030118 ("fbdev: Improve performance of cfb_imageblit()")
Reported-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Tested-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: default avatarJavier Martinez Canillas <javierm@redhat.com>
Tested-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220313192952.12058-3-tzimmermann@suse.de
parent 40faaf80

drivers/video/fbdev/core/cfbimgblt.c

+24 −4
Original line number Diff line number Diff line
@@ -218,7 +218,7 @@ static inline void fast_imageblit(const struct fb_image *image, struct fb_info * 
{

	u32 fgx = fgcolor, bgx = bgcolor, bpp = p->var.bits_per_pixel;

	u32 ppw = 32/bpp, spitch = (image->width + 7)/8;

	u32 bit_mask, eorx;

	u32 bit_mask, eorx, shift;

	const char *s = image->data, *src;

	u32 __iomem *dst;

	const u32 *tab = NULL;
@@ -259,17 +259,23 @@ static inline void fast_imageblit(const struct fb_image *image, struct fb_info * 


	for (i = image->height; i--; ) {

		dst = (u32 __iomem *)dst1;

		shift = 8;

		src = s;



		/*

		 * Manually unroll the per-line copying loop for better

		 * performance. This works until we processed the last

		 * completely filled source byte (inclusive).

		 */

		switch (ppw) {

		case 4: /* 8 bpp */

			for (j = k; j; j -= 2, ++src) {

			for (j = k; j >= 2; j -= 2, ++src) {

				FB_WRITEL(colortab[(*src >> 4) & bit_mask], dst++);

				FB_WRITEL(colortab[(*src >> 0) & bit_mask], dst++);

			}

			break;

		case 2: /* 16 bpp */

			for (j = k; j; j -= 4, ++src) {

			for (j = k; j >= 4; j -= 4, ++src) {

				FB_WRITEL(colortab[(*src >> 6) & bit_mask], dst++);

				FB_WRITEL(colortab[(*src >> 4) & bit_mask], dst++);

				FB_WRITEL(colortab[(*src >> 2) & bit_mask], dst++);
@@ -277,7 +283,7 @@ static inline void fast_imageblit(const struct fb_image *image, struct fb_info * 
			}

			break;

		case 1: /* 32 bpp */

			for (j = k; j; j -= 8, ++src) {

			for (j = k; j >= 8; j -= 8, ++src) {

				FB_WRITEL(colortab[(*src >> 7) & bit_mask], dst++);

				FB_WRITEL(colortab[(*src >> 6) & bit_mask], dst++);

				FB_WRITEL(colortab[(*src >> 5) & bit_mask], dst++);
@@ -290,6 +296,20 @@ static inline void fast_imageblit(const struct fb_image *image, struct fb_info * 
			break;

		}



		/*

		 * For image widths that are not a multiple of 8, there

		 * are trailing pixels left on the current line. Print

		 * them as well.

		 */

		for (; j--; ) {

			shift -= ppw;

			FB_WRITEL(colortab[(*src >> shift) & bit_mask], dst++);

			if (!shift) {

				shift = 8;

				++src;

			}

		}



		dst1 += p->fix.line_length;

		s += spitch;

	}