[PATCH 10/10] tgafb: avoid restriction on modes with line lengthnot a multiple of 64

From: Mikulas Patocka
Date: Thu Jan 23 2014 - 13:20:05 EST


In tgafb there is a restriction that prevents the user from setting a
videomode with line length not a multiple of 64 bytes (for example,
800x600 is not allowed).

The reason for this restriction it that functions copyarea_line_8bpp and
copyarea_line_32bpp can not handle a line length that is not a multiple
of 64 bytes.

This patch removes this restriction on mode setting and makes sure that
the functions copyarea_line_8bpp and copyarea_line_32bpp are called only
if line length is a multiple of 64 bytes. If we set a mode 800x600,
the functions copyarea_line_8bpp and copyarea_line_32bpp are not used,
generic functions for copying are used instead and it works just fine.

Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>

---
drivers/video/tgafb.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

Index: linux-3.8-rc3-fast/drivers/video/tgafb.c
===================================================================
--- linux-3.8-rc3-fast.orig/drivers/video/tgafb.c 2013-01-10 23:43:44.000000000 +0100
+++ linux-3.8-rc3-fast/drivers/video/tgafb.c 2013-01-10 23:43:49.000000000 +0100
@@ -198,8 +198,8 @@ tgafb_check_var(struct fb_var_screeninfo
return -EINVAL;

/* Some of the acceleration routines assume the line width is
- a multiple of 64 bytes. */
- if (var->xres * (par->tga_type == TGA_TYPE_8PLANE ? 1 : 4) % 64)
+ a multiple of 8 bytes. */
+ if (var->xres * (par->tga_type == TGA_TYPE_8PLANE ? 1 : 4) % 8)
return -EINVAL;

return 0;
@@ -1286,7 +1286,7 @@ tgafb_copyarea(struct fb_info *info, con
bpp = info->var.bits_per_pixel;

/* Detect copies of the entire line. */
- if (width * (bpp >> 3) == line_length) {
+ if (!(line_length & 63) && width * (bpp >> 3) == line_length) {
if (bpp == 8)
copyarea_line_8bpp(info, dy, sy, height, width);
else
--
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