On Wed, 06 Aug 2025, Jani Nikula <jani.nik...@linux.intel.com> wrote:
> On Wed, 06 Aug 2025, Jouni Högander <jouni.hogan...@intel.com> wrote:
>> Parsed divider p will overflow and is considered being valid divider in
>> case pll_ctl == 0.
>>
>> Fix this by using do while.
>>
>> Signed-off-by: Jouni Högander <jouni.hogan...@intel.com>
>> ---
>> drivers/gpu/drm/i915/display/vlv_dsi_pll.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/vlv_dsi_pll.c
>> b/drivers/gpu/drm/i915/display/vlv_dsi_pll.c
>> index b52463fdec47..f56985c3da54 100644
>> --- a/drivers/gpu/drm/i915/display/vlv_dsi_pll.c
>> +++ b/drivers/gpu/drm/i915/display/vlv_dsi_pll.c
>> @@ -142,10 +142,10 @@ static int vlv_dsi_pclk(struct intel_encoder *encoder,
>> pll_div &= DSI_PLL_M1_DIV_MASK;
>> pll_div = pll_div >> DSI_PLL_M1_DIV_SHIFT;
>>
>> - while (pll_ctl) {
>> + do {
>> pll_ctl = pll_ctl >> 1;
>> p++;
>> - }
>> + } while (pll_ctl);
>> p--;
>
> Alternatively, use p = lfs(pll_ctl), check the return value, and p--
> after that?
Should be fls(). (Find last set.)
>
>
>>
>> if (!p) {
--
Jani Nikula, Intel
