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atmel_lcdfb: validate display timings

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Setting a display timing parameter too high or too low may cause it to
wrap around and thus become completely wrong. Validate the timings in
atmel_lcdfb_check_var() and saturate to the highest or lowest possible
value if necessary.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Haavard Skinnemoen 2008-02-06 01:39:11 -08:00 committed by Linus Torvalds
parent 529e55b6a5
commit 162b3a0849
2 changed files with 27 additions and 7 deletions
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20
drivers/video/atmel_lcdfb.c
View File

@ -203,6 +203,26 @@ static int atmel_lcdfb_check_var(struct fb_var_screeninfo *var,
var->transp.offset = var->transp.length = 0;
var->xoffset = var->yoffset = 0;
/* Saturate vertical and horizontal timings at maximum values */
var->vsync_len = min_t(u32, var->vsync_len,
(ATMEL_LCDC_VPW >> ATMEL_LCDC_VPW_OFFSET) + 1);
var->upper_margin = min_t(u32, var->upper_margin,
ATMEL_LCDC_VBP >> ATMEL_LCDC_VBP_OFFSET);
var->lower_margin = min_t(u32, var->lower_margin,
ATMEL_LCDC_VFP);
var->right_margin = min_t(u32, var->right_margin,
(ATMEL_LCDC_HFP >> ATMEL_LCDC_HFP_OFFSET) + 1);
var->hsync_len = min_t(u32, var->hsync_len,
(ATMEL_LCDC_HPW >> ATMEL_LCDC_HPW_OFFSET) + 1);
var->left_margin = min_t(u32, var->left_margin,
ATMEL_LCDC_HBP + 1);
/* Some parameters can't be zero */
var->vsync_len = max_t(u32, var->vsync_len, 1);
var->right_margin = max_t(u32, var->right_margin, 1);
var->hsync_len = max_t(u32, var->hsync_len, 1);
var->left_margin = max_t(u32, var->left_margin, 1);
switch (var->bits_per_pixel) {
case 1:
case 2:

14
include/video/atmel_lcdc.h
View File

@ -115,20 +115,20 @@ struct atmel_lcdfb_info {
#define ATMEL_LCDC_MEMOR_LITTLE (1 << 31)
#define ATMEL_LCDC_TIM1 0x0808
#define ATMEL_LCDC_VFP (0xff << 0)
#define ATMEL_LCDC_VFP (0xffU << 0)
#define ATMEL_LCDC_VBP_OFFSET 8
#define ATMEL_LCDC_VBP (0xff << ATMEL_LCDC_VBP_OFFSET)
#define ATMEL_LCDC_VBP (0xffU << ATMEL_LCDC_VBP_OFFSET)
#define ATMEL_LCDC_VPW_OFFSET 16
#define ATMEL_LCDC_VPW (0x3f << ATMEL_LCDC_VPW_OFFSET)
#define ATMEL_LCDC_VPW (0x3fU << ATMEL_LCDC_VPW_OFFSET)
#define ATMEL_LCDC_VHDLY_OFFSET 24
#define ATMEL_LCDC_VHDLY (0xf << ATMEL_LCDC_VHDLY_OFFSET)
#define ATMEL_LCDC_VHDLY (0xfU << ATMEL_LCDC_VHDLY_OFFSET)
#define ATMEL_LCDC_TIM2 0x080c
#define ATMEL_LCDC_HBP (0xff << 0)
#define ATMEL_LCDC_HBP (0xffU << 0)
#define ATMEL_LCDC_HPW_OFFSET 8
#define ATMEL_LCDC_HPW (0x3f << ATMEL_LCDC_HPW_OFFSET)
#define ATMEL_LCDC_HPW (0x3fU << ATMEL_LCDC_HPW_OFFSET)
#define ATMEL_LCDC_HFP_OFFSET 21
#define ATMEL_LCDC_HFP (0x7ff << ATMEL_LCDC_HFP_OFFSET)
#define ATMEL_LCDC_HFP (0x7ffU << ATMEL_LCDC_HFP_OFFSET)
#define ATMEL_LCDC_LCDFRMCFG 0x0810
#define ATMEL_LCDC_LINEVAL (0x7ff << 0)