drm/i915/display: Update calculation to avoid overflow

Update calculation to avoid overflow.

-v2:
Remove extra line between cc and signed-off.

Fixes: 1676ecd303ac ("drm/i915: Compute CMRR and calculate vtotal")
Cc: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Cc: Suraj Kandpal <suraj.kandpal@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240614044213.377710-1-mitulkumar.ajitkumar.golani@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index eb5b62b54d32df9a92e8d79e2430d2a6d1a9ff91..6430da25957ddaf36b01947d283e7f508643c402 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -147,10 +147,11 @@ cmrr_get_vtotal(struct intel_crtc_state *crtc_state, bool video_mode_required)
                multiplier_n = 1000;
        }
 
-       crtc_state->cmrr.cmrr_n =
-               desired_refresh_rate * adjusted_mode->crtc_htotal * multiplier_n;
-       vtotal = (adjusted_mode->crtc_clock * 1000 * multiplier_n) / crtc_state->cmrr.cmrr_n;
-       adjusted_pixel_rate = adjusted_mode->crtc_clock * 1000 * multiplier_m;
+       crtc_state->cmrr.cmrr_n = mul_u32_u32(desired_refresh_rate * adjusted_mode->crtc_htotal,
+                                             multiplier_n);
+       vtotal = DIV_ROUND_UP_ULL(mul_u32_u32(adjusted_mode->crtc_clock * 1000, multiplier_n),
+                                 crtc_state->cmrr.cmrr_n);
+       adjusted_pixel_rate = mul_u32_u32(adjusted_mode->crtc_clock * 1000, multiplier_m);
        crtc_state->cmrr.cmrr_m = do_div(adjusted_pixel_rate, crtc_state->cmrr.cmrr_n);
 
        return vtotal;