[1/2] drm/rockchip: Properly adjust to a true clock in adjusted_mode
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Message ID 20190614224730.98622-1-dianders@chromium.org
State New
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  • [1/2] drm/rockchip: Properly adjust to a true clock in adjusted_mode
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Commit Message

Doug Anderson June 14, 2019, 10:47 p.m. UTC
When fixing up the clock in vop_crtc_mode_fixup() we're not doing it
quite correctly.  Specifically if we've got the true clock 266666667 Hz,
we'll perform this calculation:
   266666667 / 1000 => 266666

Later when we try to set the clock we'll do clk_set_rate(266666 *
1000).  The common clock framework won't actually pick the proper clock
in this case since it always wants clocks <= the specified one.

Let's solve this by using DIV_ROUND_UP.

Fixes: b59b8de31497 ("drm/rockchip: return a true clock rate to adjusted_mode")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Yakir Yang <ykk@rock-chips.com>
---
Back in 2016 Mark Yao said he applied this to his drm fixes [1], but it's
2019 and it's still missing so I'm posting again.

[1] https://patchwork.freedesktop.org/patch/103872/

 drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Heiko Stuebner June 16, 2019, 1:41 p.m. UTC | #1
Am Samstag, 15. Juni 2019, 00:47:29 CEST schrieb Douglas Anderson:
> When fixing up the clock in vop_crtc_mode_fixup() we're not doing it
> quite correctly.  Specifically if we've got the true clock 266666667 Hz,
> we'll perform this calculation:
>    266666667 / 1000 => 266666
> 
> Later when we try to set the clock we'll do clk_set_rate(266666 *
> 1000).  The common clock framework won't actually pick the proper clock
> in this case since it always wants clocks <= the specified one.
> 
> Let's solve this by using DIV_ROUND_UP.
> 
> Fixes: b59b8de31497 ("drm/rockchip: return a true clock rate to adjusted_mode")
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> Signed-off-by: Sean Paul <seanpaul@chromium.org>
> Reviewed-by: Yakir Yang <ykk@rock-chips.com>

I gave both patches a testrun on rk3288, rk3328 and rk3399 and
applied them to drm-misc-next thereafter


Thanks
Heiko

Patch
diff mbox series

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index e4580d8f21e1..d124f34ab9fc 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -1006,7 +1006,8 @@  static bool vop_crtc_mode_fixup(struct drm_crtc *crtc,
 	struct vop *vop = to_vop(crtc);
 
 	adjusted_mode->clock =
-		clk_round_rate(vop->dclk, mode->clock * 1000) / 1000;
+		DIV_ROUND_UP(clk_round_rate(vop->dclk, mode->clock * 1000),
+			     1000);
 
 	return true;
 }