Commit 5b34ab52 authored by Ville Syrjälä's avatar Ville Syrjälä
Browse files

drm/modes: Switch to 64bit maths to avoid integer overflow 



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: stable@vger.kernel.org
Reported-by: default avatarRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201022194256.30978-1-ville.syrjala@linux.intel.com


Tested-by: default avatarRandy Dunlap <rdunlap@infradead.org>
Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
parent 625f8fb5

drivers/gpu/drm/drm_modes.c

+2 −2
Original line number Diff line number Diff line
@@ -762,7 +762,7 @@ int drm_mode_vrefresh(const struct drm_display_mode *mode) 
	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_display_mode *mode) 
	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);