Hi Andy, On Sun Jun 8, 2025 at 2:10 PM CEST, Andy Yan wrote: > At 2025-06-08 19:08:50, "Diederik de Haas" <didi.deb...@cknow.org> wrote: >>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. > > I have conducted tests on both rk3566-box-demo (with drm set to y) and > rk3568-lubancat-2 (with drm set to m), > but I was unable to reproduce this issue. Could you two please share your > kernel defconfig and the corresponding kernel startup logs? > Additionally, both of my two boards tested with HDMI output. What kind of > display interface does your board use for output?
I wasn't able to reproduce this issue on my PINE64 Quartz-B (rk3566) with HDMI output either, but the problem is present on a PineTab2 [1] (also rk3566) which uses a MIPI DSI connection to the display panel. Kernel config: https://paste.sr.ht/~diederik/aa747ed170aa01cc759fbe1ffd9cebe8c887b10b dmesg kernel 6.14-rc1: https://paste.sr.ht/~diederik/733fbf8bb7f6aee8b68cf5a652157d445462c24a dmesg kernel 6.14-rc1 with Piotr's patch: https://paste.sr.ht/~diederik/db1af672cfb611acbfbdf35adb6f170e5c38febc Both dmesg outputs contain a suspend-resume cycle. I'm using a USB Wi-Fi adapter for the wireless connection. [1] https://wiki.pine64.org/wiki/PineTab2 Happy to provide more info and/or do some tests. Cheers, Diederik >>> 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.
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