Hi,
Am Freitag, 5. Januar 2024, 10:04:55 CET schrieb Andy Yan:
> On 1/4/24 23:58, Heiko Stübner wrote:
> > Am Donnerstag, 4. Januar 2024, 15:39:50 CET schrieb Cristian Ciocaltea:
> >> Commit 5a028e8f062f ("drm/rockchip: vop2: Add support for rk3588")
> >> introduced a variable which ended up being unused. Remove it.
> >>
> >> rockchip_drm_vop2.c:1688:23: warning: variable ‘if_dclk_rate’ set but not used [-Wunused-but-set-variable]
> >>
> >> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxxxxxx>
> >
> > in general, please don't send non-series patches as replies to other patches.
> > It confuses tooling like b4 way too often, as this patch is not designated
> > as a 2/2 (similar to the first one not being 1/2).
> >
> >> ---
> >> drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 2 --
> >> 1 file changed, 2 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> >> index 44508c2dd614..923985d4161b 100644
> >> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> >> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> >> @@ -1685,7 +1685,6 @@ static unsigned long rk3588_calc_cru_cfg(struct vop2_video_port *vp, int id,
> >> unsigned long dclk_core_rate = v_pixclk >> 2;
> >> unsigned long dclk_rate = v_pixclk;
> >> unsigned long dclk_out_rate;
> >> - unsigned long if_dclk_rate;
> >> unsigned long if_pixclk_rate;
> >> int K = 1;
> >>
> >> @@ -1700,7 +1699,6 @@ static unsigned long rk3588_calc_cru_cfg(struct vop2_video_port *vp, int id,
> >> }
> >>
> >> if_pixclk_rate = (dclk_core_rate << 1) / K;
> >> - if_dclk_rate = dclk_core_rate / K;
> >> /*
> >> * *if_pixclk_div = dclk_rate / if_pixclk_rate;
> >> * *if_dclk_div = dclk_rate / if_dclk_rate;
> >> */
> > *if_pixclk_div = 2;
> > *if_dclk_div = 4;
> >
> > with the code continuing with those static constants but the comment
> > showing a forumula, I do hope Andy can provide a bit of insight into
> > what is happening here.
> >
> > I.e. I'd really like to understand if that really is just a remnant or
> > something different is needed.
>
> This is not a remnant, in my V1, I calculate all the div by formula, but Sascha prefer
> more for a constants value[0], so I keep this formula as comments to indicate how these value come from.
>
> [0]https://patchwork.kernel.org/project/linux-rockchip/patch/20231114112855.1771372-1-andyshrk@xxxxxxx/
thanks for referencing the source of the change.
Leaving the formula in there was the right choice I think
That still leaves the issue with the "unused" warning.
@Christan: in the hdmi block itself can you move the
if_dclk_rate = dclk_core_rate / K;
to the comment block please? And possibly reference the use
of the static values in the comment message.
The if_dclk_rate var declaration at the top of the function can of course
go away.
That way we still keep documenting how these values came to be:
/*
* if_dclk_rate = dclk_core_rate / K;
* *if_pixclk_div = dclk_rate / if_pixclk_rate;
* *if_dclk_div = dclk_rate / if_dclk_rate;
*/
Thanks
Heiko
