Re: [Intel-gfx] [PATCH v2] drm/i915/tv: avoid possible division by zero

[Su Hui]

On 2023/7/25 13:51, Dan Carpenter wrote:

The reason why the first five attempts had bugs is because we are
trying to write it in the most complicated way possible, shifting by
logical not what?

Wonderful! Should I add your name as signed-of-by?
I will send a v3 patch later.
Really thanks for your help!

Su Hui

regards,
dan carpenter

diff --git a/drivers/gpu/drm/i915/display/intel_tv.c 
b/drivers/gpu/drm/i915/display/intel_tv.c
index 36b479b46b60..6997b6cb1df2 100644
--- a/drivers/gpu/drm/i915/display/intel_tv.c
+++ b/drivers/gpu/drm/i915/display/intel_tv.c
@@ -988,7 +988,13 @@ 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);
+       int div = tv_mode->oversample;
+
+       if (!tv_mode->progressive)
+               div >>= 1;
+       if (div == 0)
+               div = 1;
+       mode->clock = clock / div;

/*

         * tv_mode horizontal timings:
@@ -1135,6 +1141,8 @@ intel_tv_get_config(struct intel_encoder *encoder,
                break;
        default:
                tv_mode.oversample = 1;
+               WARN_ON_ONCE(!tv_mode.progressive);
+               tv_mode.progressive = true;
                break;
        }