| Message ID | 20220313192952.12058-2-tzimmermann@suse.de |
|---|---|
| State | New |
| Headers | show |
| Series | fbdev: Fix image blitting for arbitrary image widths | expand |
Hi Thomas, On Sun, Mar 13, 2022 at 8:29 PM Thomas Zimmermann <tzimmermann@suse.de> wrote: > Commit 6f29e04938bf ("fbdev: Improve performance of sys_imageblit()") > broke sys_imageblit() for image width 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 <tzimmermann@suse.de> Thanks for fixing! This was very valuable for hammering the bugs out of ssd130xdrm and the xrgb888-to-mono conversion... Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
Hello Thomas, On 3/13/22 20:29, Thomas Zimmermann wrote: > Commit 6f29e04938bf ("fbdev: Improve performance of sys_imageblit()") > broke sys_imageblit() for image width 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 <tzimmermann@suse.de> > Fixes: 6f29e04938bf ("fbdev: Improve performance of sys_imageblit()") > Cc: Thomas Zimmermann <tzimmermann@suse.de> > Cc: Javier Martinez Canillas <javierm@redhat.com> > Cc: Sam Ravnborg <sam@ravnborg.org> > --- Looks good to me. Also Marek and Geert mentioned that fixes the issue they were seeing. Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
diff --git a/drivers/video/fbdev/core/sysimgblt.c b/drivers/video/fbdev/core/sysimgblt.c index 722c327a381b..335e92b813fc 100644 --- a/drivers/video/fbdev/core/sysimgblt.c +++ b/drivers/video/fbdev/core/sysimgblt.c @@ -188,7 +188,7 @@ static void fast_imageblit(const struct fb_image *image, struct fb_info *p, { 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 *dst; const u32 *tab; @@ -229,17 +229,23 @@ static void fast_imageblit(const struct fb_image *image, struct fb_info *p, for (i = image->height; i--; ) { dst = 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) { *dst++ = colortab[(*src >> 4) & bit_mask]; *dst++ = colortab[(*src >> 0) & bit_mask]; } break; case 2: /* 16 bpp */ - for (j = k; j; j -= 4, ++src) { + for (j = k; j >= 4; j -= 4, ++src) { *dst++ = colortab[(*src >> 6) & bit_mask]; *dst++ = colortab[(*src >> 4) & bit_mask]; *dst++ = colortab[(*src >> 2) & bit_mask]; @@ -247,7 +253,7 @@ static void fast_imageblit(const struct fb_image *image, struct fb_info *p, } break; case 1: /* 32 bpp */ - for (j = k; j; j -= 8, ++src) { + for (j = k; j >= 8; j -= 8, ++src) { *dst++ = colortab[(*src >> 7) & bit_mask]; *dst++ = colortab[(*src >> 6) & bit_mask]; *dst++ = colortab[(*src >> 5) & bit_mask]; @@ -259,6 +265,21 @@ static void fast_imageblit(const struct fb_image *image, struct fb_info *p, } 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; + *dst++ = colortab[(*src >> shift) & bit_mask]; + if (!shift) { + shift = 8; + ++src; + } + } + dst1 += p->fix.line_length; s += spitch; }
Commit 6f29e04938bf ("fbdev: Improve performance of sys_imageblit()") broke sys_imageblit() for image width 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 <tzimmermann@suse.de> Fixes: 6f29e04938bf ("fbdev: Improve performance of sys_imageblit()") Cc: Thomas Zimmermann <tzimmermann@suse.de> Cc: Javier Martinez Canillas <javierm@redhat.com> Cc: Sam Ravnborg <sam@ravnborg.org> --- drivers/video/fbdev/core/sysimgblt.c | 29 ++++++++++++++++++++++++---- 1 file changed, 25 insertions(+), 4 deletions(-)