unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
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video: da8xx-fb: fb_check_var enhancement

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Check whether "struct fb_var_screeninfo" fields are sane, if not
update it to be within allowed limits.

If user sends down buggy "var" values, this will bring those within
allowable limits. And fb_set_par is not supposed to change "var"
values, fb_check_var has to ensure that values are proper.

Signed-off-by: Afzal Mohammed <afzal@ti.com>
Signed-off-by: Darren Etheridge <detheridge@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
This commit is contained in:
Afzal Mohammed 2013-08-05 17:02:20 -05:00 committed by Tomi Valkeinen
parent 3b2f64d00c
commit 87dac71d6d
1 changed files with 18 additions and 0 deletions
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18
drivers/video/da8xx-fb.c
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@ -888,6 +888,9 @@ static int fb_check_var(struct fb_var_screeninfo *var,
struct fb_info *info)
{
int err = 0;
struct da8xx_fb_par *par = info->par;
int bpp = var->bits_per_pixel >> 3;
unsigned long line_size = var->xres_virtual * bpp;
if (var->bits_per_pixel > 16 && lcd_revision == LCD_VERSION_1)
return -EINVAL;
@ -955,6 +958,21 @@ static int fb_check_var(struct fb_var_screeninfo *var,
var->green.msb_right = 0;
var->blue.msb_right = 0;
var->transp.msb_right = 0;
if (line_size * var->yres_virtual > par->vram_size)
var->yres_virtual = par->vram_size / line_size;
if (var->yres > var->yres_virtual)
var->yres = var->yres_virtual;
if (var->xres > var->xres_virtual)
var->xres = var->xres_virtual;
if (var->xres + var->xoffset > var->xres_virtual)
var->xoffset = var->xres_virtual - var->xres;
if (var->yres + var->yoffset > var->yres_virtual)
var->yoffset = var->yres_virtual - var->yres;
return err;
}