On Tue, 26 Oct 2021, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote:
> On Tue, Oct 26, 2021 at 12:34:07PM +0300, Jani Nikula wrote:
>> 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@xxxxxxxxx>
>> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
>
> Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Thanks, pushed.
BR,
Jani.
>
>> ---
>> 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 f5dc2126d140..537c689a1528 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>> @@ -352,7 +352,7 @@ 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;
>> }
>>
>> --
>> 2.30.2
--
Jani Nikula, Intel Open Source Graphics Center
