From 7438f52b578afbac3807396531361aac85d43a06 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Sun, 13 Mar 2022 20:29:52 +0100 Subject: [PATCH] fbdev: Fix cfb_imageblit() for arbitrary image widths Commit 0d03011894d2 ("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: Thomas Zimmermann Fixes: 0d03011894d2 ("fbdev: Improve performance of cfb_imageblit()") Reviewed-by: Javier Martinez Canillas Acked-by: Daniel Vetter Tested-by: Marek Szyprowski Reported-by: Marek Szyprowski Cc: Thomas Zimmermann Cc: Javier Martinez Canillas Cc: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/20220313192952.12058-3-tzimmermann@suse.de --- drivers/video/fbdev/core/cfbimgblt.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) diff --git a/drivers/video/fbdev/core/cfbimgblt.c b/drivers/video/fbdev/core/cfbimgblt.c index 7361cfabdd85..9ebda4e0dc7a 100644 --- a/drivers/video/fbdev/core/cfbimgblt.c +++ b/drivers/video/fbdev/core/cfbimgblt.c @@ -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; }