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V4L/DVB (3704): Fix some errors on bttv_risc_overlay

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There are tree mistakes on bttv_risc_overlay.
1) When skip_odd is true, the number of lines for which
instructions are written is (height+1)/2, not height/2.
2) This occurs when clipping: the number of instruction bytes
written can be as much as 8 + 12*nclips, not 8 + 8*nclips, as
currently estimated.
3) Coverity check were wrong with nskips=0, since it means that
it can clipped at most one line.

Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
This commit is contained in:
Duncan Sands 2006-04-02 04:14:57 -03:00 committed by Mauro Carvalho Chehab
parent faa88df860
commit 3203f94a25
1 changed files with 6 additions and 8 deletions
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14
drivers/media/video/bt8xx/bttv-risc.c
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@ -233,7 +233,7 @@ bttv_risc_overlay(struct bttv *btv, struct btcx_riscmem *risc,
const struct bttv_format *fmt, struct bttv_overlay *ov,
int skip_even, int skip_odd)
{
int instructions,rc,line,maxy,start,end,skip,nskips;
int dwords,rc,line,maxy,start,end,skip,nskips;
struct btcx_skiplist *skips;
u32 *rp,ri,ra;
u32 addr;
@ -242,12 +242,12 @@ bttv_risc_overlay(struct bttv *btv, struct btcx_riscmem *risc,
if (NULL == (skips = kmalloc(sizeof(*skips) * ov->nclips,GFP_KERNEL)))
return -ENOMEM;
/* estimate risc mem: worst case is (clip+1) * lines instructions
/* estimate risc mem: worst case is (1.5*clip+1) * lines instructions
+ sync + jump (all 2 dwords) */
instructions = (ov->nclips + 1) *
((skip_even || skip_odd) ? ov->w.height>>1 : ov->w.height);
instructions += 2;
if ((rc = btcx_riscmem_alloc(btv->c.pci,risc,instructions*8)) < 0) {
dwords = (3 * ov->nclips + 2) *
((skip_even || skip_odd) ? (ov->w.height+1)>>1 : ov->w.height);
dwords += 4;
if ((rc = btcx_riscmem_alloc(btv->c.pci,risc,dwords*4)) < 0) {
kfree(skips);
return rc;
}
@ -276,8 +276,6 @@ bttv_risc_overlay(struct bttv *btv, struct btcx_riscmem *risc,
if (line > maxy)
btcx_calc_skips(line, ov->w.width, &maxy,
skips, &nskips, ov->clips, ov->nclips);
else
nskips = 0;
/* write out risc code */
for (start = 0, skip = 0; start < ov->w.width; start = end) {