On 2023/7/25 01:35, Andi Shyti wrote:
On Tue, Jul 18, 2023 at 09:32:17AM +0800, Su Hui wrote:
Clang warning: drivers/gpu/drm/i915/display/intel_tv.c:
line 991, column 22 Division by zero.
Assuming tv_mode->oversample=1 and (!tv_mode->progressive)=1,
then division by zero will happen.
Fixes: 1bba5543e4fe ("drm/i915: Fix TV encoder clock computation")
Signed-off-by: Su Hui <suhui@xxxxxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_tv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/display/intel_tv.c b/drivers/gpu/drm/i915/display/intel_tv.c
index 36b479b46b60..f59553f7c132 100644
--- a/drivers/gpu/drm/i915/display/intel_tv.c
+++ b/drivers/gpu/drm/i915/display/intel_tv.c
@@ -988,7 +988,7 @@ intel_tv_mode_to_mode(struct drm_display_mode *mode,
const struct tv_mode *tv_mode,
int clock)
{
- mode->clock = clock / (tv_mode->oversample >> !tv_mode->progressive);
+ mode->clock = clock / tv_mode->oversample << !tv_mode->progressive;
but this does not provide the same value. Try with:
8 / (2 >> 1)
and
8 / 2 << 1
They are definitely different.
The real check could be:
if (!(tv_mode->oversample >> 1))
return ...
But first I would check if that's actually possible.
Oh, I have a v3 patch, like this:
- mode->clock = clock / (tv_mode->oversample >>
!tv_mode->progressive);
+ mode->clock = clock;
+ if (tv_mode->oversample >> !tv_mode->progressive)
+ mode->clock /= tv_mode->oversample >> 1;
But I'm not sure does it need to print some error messages or do some
things when
"tv_mode->oversample << !tv_mode->progressive" is zero?
If all right , I will send this v3 patch.
Su Hui
Andi
