From bb80807a7d8866b19cbe2f35d15576d0168e42d9 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula@intel.com>
Date: Tue, 26 Oct 2021 12:34:07 +0300
Subject: drm/i915/dp: fix integer overflow in 128b/132b data rate calculation
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Alt-commit: bf0d608b55d9b7f426031dfd9f08d9df36c94728
Git-commit: 02295cf3897aa04072d4d25c7ae642eb86e2d63f
Patch-mainline: v5.16-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
The intermediate value 1000000 * 10 * 9671 overflows 32 bits, so force
promotion to a bigger type.
From the logs:
[drm:intel_dp_compute_config [i915]] DP link rate required 3657063 available -580783288
v2: Use mul_u32_u32() (Ville)
Fixes: 48efd014f0ea ("drm/i915/dp: add max data rate calculation for UHBR rates")
Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Ville Syrj채l채 <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrj채l채 <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211026093407.11381-1-jani.nikula@intel.com
(cherry picked from commit bf0d608b55d9b7f426031dfd9f08d9df36c94728)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/display/intel_dp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 0a92c9f4b09e..be883469d2fc 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -287,7 +287,7 @@ intel_dp_max_data_rate(int max_link_rate, int max_lanes)
*/
int max_link_rate_kbps = max_link_rate * 10;
- max_link_rate_kbps = DIV_ROUND_CLOSEST_ULL(max_link_rate_kbps * 9671, 10000);
+ max_link_rate_kbps = DIV_ROUND_CLOSEST_ULL(mul_u32_u32(max_link_rate_kbps, 9671), 10000);
max_link_rate = max_link_rate_kbps / 8;
}
--
2.38.1