Hi Piotr, On Sat Jun 7, 2025 at 5:32 PM CEST, Piotr Zalewski wrote: > On Thursday, June 5th, 2025 at 10:13 PM, Diederik de Haas > <didi.deb...@cknow.org> wrote: >> Since kernel 6.14-rc1 I have the problem that visual output is no longer >> shown on my PineTab2 and a `git bisect` pointed to this patch/commit >> as the culprit. What is important to note is that `CONFIG_DRM=m` seems >> to be required as the problem does not occur with `CONFIG_DRM=y`. >> >> Near the end of my bisect session, something interesting occurred. >> I was booted into a 'bad' kernel (ie no visual output) and when I >> started to build my final kernel, I closed the lid of the PineTab2 which >> made it go into suspend. When my final kernel was built, I opened the >> lid again, which made it resume, to transfer my final kernel to it. >> And much to my surprise, I then did have visual output. >> When I read the (below) commit message of the 'offending' commit, it may >> not be such a surprise after all. >> >> I did try it on a Quartz64-B (also rk3566) and it did not have any issue >> (output via HDMI). >> I don't know what the cause for this issue is, hopefully you do. > > I tested and confirmed that this happens with drm=m but also in my case > it happened when drm=y. After some testing I found out that at boot modeset
Interesting that it also happened with drm=y. As you're more knowledgeable then I am with this, maybe look through https://lists.sr.ht/~diederik/pine64-discuss/<d9am2oolreo0.2jmai42j06...@cknow.org> to see if you may spot something relevant? > happened twice and at short interval and since this patch allows for gamma > LUT update regardless of color_mgmt_changed state this makes DSP CTRL GAMMA > LUT EN bit to be unset twice too. It seems that VOP does not like it. I Happy to see you found the cause :-) Do you happen to know why it was unset twice? That sounds suboptimal. But (IIUC) setting a bit to a value it already has causing issues, sounds surprising as well. > patched vop2_vp_dsp_lut_disable function so that dsp_ctrl is set only if > GAMMA LUT EN bit is set. I checked that this also does not break the gamma > lut functionality with emphasis on out-of/into suspend behavior. > > diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c > b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c > index d0f5fea15e21..7ddf311b38c6 100644 > --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c > +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c > @@ -897,6 +897,9 @@ static void vop2_vp_dsp_lut_disable(struct > vop2_video_port *vp) > { > u32 dsp_ctrl = vop2_vp_read(vp, RK3568_VP_DSP_CTRL); > > + if ((dsp_ctrl & RK3568_VP_DSP_CTRL__DSP_LUT_EN) == 0) > + return; > + > dsp_ctrl &= ~RK3568_VP_DSP_CTRL__DSP_LUT_EN; > vop2_vp_write(vp, RK3568_VP_DSP_CTRL, dsp_ctrl); > } I built a kernel with 6.14-rc1 + this patch and can confirm the screen has output again :-) > I will wait with sending a patch because maybe Andy has something to add > to this. Sounds like a plan. It could be that this issue surfaced an underlaying issue and if so, fixing that would be even better. > Best regards, Piotr Zalewski Thanks a lot! Cheers, Diederik
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