From: Ville Syrjälä <ville.syrj...@linux.intel.com>

commit 5b34ab52401f0f1f191bcb83a182c83b506f4763 upstream.

The new >8k CEA modes have dotclocks reaching 5.94 GHz, which
means our clock*1000 will now overflow the 32bit unsigned
integer. Switch to 64bit maths to avoid it.

Cc: sta...@vger.kernel.org
Reported-by: Randy Dunlap <rdun...@infradead.org>
Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
Link: 
https://patchwork.freedesktop.org/patch/msgid/20201022194256.30978-1-ville.syrj...@linux.intel.com
Tested-by: Randy Dunlap <rdun...@infradead.org>
Reviewed-by: Chris Wilson <ch...@chris-wilson.co.uk>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/gpu/drm/drm_modes.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -762,7 +762,7 @@ int drm_mode_vrefresh(const struct drm_d
        if (mode->htotal == 0 || mode->vtotal == 0)
                return 0;
 
-       num = mode->clock * 1000;
+       num = mode->clock;
        den = mode->htotal * mode->vtotal;
 
        if (mode->flags & DRM_MODE_FLAG_INTERLACE)
@@ -772,7 +772,7 @@ int drm_mode_vrefresh(const struct drm_d
        if (mode->vscan > 1)
                den *= mode->vscan;
 
-       return DIV_ROUND_CLOSEST(num, den);
+       return DIV_ROUND_CLOSEST_ULL(mul_u32_u32(num, 1000), den);
 }
 EXPORT_SYMBOL(drm_mode_vrefresh);
 


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