Hi Piotr, On Sat Jun 28, 2025 at 8:11 PM CEST, 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 because of timing 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 on Pinetab2. > > [1] > https://lore.kernel.org/linux-rockchip/[email protected]/ > > Reported-by: Diederik de Haas <[email protected]> > Closes: > https://lore.kernel.org/linux-rockchip/[email protected]/ > Suggested-by: Andy Yan <[email protected]> > Signed-off-by: Piotr Zalewski <[email protected]> > --- > drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c > b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c > index d0f5fea15e21..241060cc24cb 100644 > --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c > +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c > @@ -2589,12 +2589,13 @@ static int vop2_win_init(struct vop2 *vop2) > } > > /* > - * The window registers are only updated when config done is written. > - * Until that they read back the old value. As we read-modify-write > - * these registers mark them as non-volatile. This makes sure we read > - * the new values from the regmap register cache. > + * The window and video port registers are only updated when config > + * done is written. Until that they read back the old value. As we > + * read-modify-write these registers mark them as non-volatile. This > + * makes sure we read the new values from the regmap register cache. > */ > static const struct regmap_range vop2_nonvolatile_range[] = { > + regmap_reg_range(RK3568_VP0_CTRL_BASE, RK3588_VP3_CTRL_BASE+255), > regmap_reg_range(0x1000, 0x23ff), > }; >
I built a 6.16-rc3 kernel with this patch and booted into it ... and it fixed the issue I reported \o/ Thus: Tested-by: Diederik de Haas <[email protected]> Thanks! Cheers, Diederik
signature.asc
Description: PGP signature
