[PATCH v2] rockchip/drm: vop2: make vp registers nonvolatile

Heiko Stuebner heiko at sntech.de
Thu Aug 14 09:46:06 UTC 2025


On Sun, 06 Jul 2025 08:36:58 +0000, Piotr Zalewski wrote:
> Make video port registers nonvolatile. As DSP_CTRL register is written
> to twice due to gamma LUT enable bit which is set outside of the main
> DSP_CTRL initialization within atomic_enable (for rk356x case it is also
> necesarry to always disable gamma LUT before writing a new LUT) there is
> a chance that DSP_CTRL value read-out in gamma LUT init/update code is
> not the one which was written by the preceding DSP_CTRL initialization
> code within atomic_enable. This might result in misconfigured DSP_CTRL
> which leads to no visual output[1]. Since DSP_CTRL write takes effect
> after VSYNC[1] the issue is not always present. When tested on Pinetab2
> with kernel 6.14 it happenes only when DRM is compiled as a module[1].
> In order to confirm that it is a timing issue I inserted 18ms udelay
> before vop2_crtc_atomic_try_set_gamma in atomic enable and compiled DRM
> as module - this has also fixed the issue.
> 
> [...]

Applied, thanks!

[1/1] rockchip/drm: vop2: make vp registers nonvolatile
      commit: a52dffaa46c2c5ff0b311c4dc1288581f7b9109e

Best regards,
-- 
Heiko Stuebner <heiko at sntech.de>


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