Re: rk3399: Graphical artifacts when running for-next

Heiko Stuebner
2019-02-21T22:07:14Z

Am Donnerstag, 21. Februar 2019, 22:52:39 CET schrieb Ezequiel Garcia:
> On Thu, 2019-02-21 at 22:48 +0100, Heiko Stuebner wrote:
> > Am Donnerstag, 21. Februar 2019, 17:38:25 CET schrieb Robert Foss:
> > > On 2/21/19 4:53 PM, Heiko Stuebner wrote:
> > > > Am Donnerstag, 21. Februar 2019, 16:46:19 CET schrieb Robert Foss:
> > > > > On 2/21/19 2:26 PM, Heiko Stuebner wrote:
> > > > > > Hi Robert,
> > > > > >
> > > > > > Am Donnerstag, 21. Februar 2019, 11:27:15 CET schrieb Robert Foss:
> > > > > > > Hey Heiko,
> > > > > > >
> > > > > > > I've just started booting the RK3399 based Radxa Rock Pi 4 on the mainline
> > > > > > > kernel. Specifically on linux-rockchip/for-next, with an additional patch
> > > > > > > adding the GPU DT node[1].
> > > > > > >
> > > > > > > Unfortunately I'm seeing an artifact on all display output[2].
> > > > > > > It, from the VT to 3D content.
> > > > > > >
> > > > > > > Is this an issue that has been encountered before?
> > > > > >
> > > > > > I haven't seen something like this before. I do test graphics
> > > > > > on most Rockchip socs regularly (right now dw-hdmi only
> > > > > > on non-rk3399 socs though).
> > > > > >
> > > > > > Did you try full linux-next as well? My for-next branch obviously
> > > > > > only carries dt/soc-driver stuff but not things like drm-misc.
> > > > > >
> > > > > > One possible issue might be the generated clocks. You could check
> > > > > > $debug/clk/clk_summary for the dclk_vopX to see if that matches
> > > > > > the suggested clock for the mode. (For example check the requested
> > > > > > rate in rockchip_vop.c against what it actually gets).
> > > > > >
> > > > >
> > > > > I had a look using the current linux-next/master, and I'm seeing the same results.
> > > > > Commit: 550f4769c7c4 - Add linux-next specific files for 20190221
> > > > >
> > > > >
> > > > > I had also look at the debugfs output:
> > > > > # cat /sys/kernel/debug/clk/clk_summary | grep dclk_vop
> > > > > dclk_vop0_div 0 1 0 27000000 0 0 50000
> > > > > dclk_vop0 0 2 0 27000000 0 0 50000
> > > > > dclk_vop0_frac 0 0 0 1350000 0 0 50000
> > > > > dclk_vop1_div 1 1 0 59400000 0 0 50000
> > > > > dclk_vop1 2 2 0 59400000 0 0 50000
> > > > > dclk_vop1_frac 0 0 0 2970000 0 0 50000
> > > > >
> > > > > But I can't find a file named rockchip_vop.c exactly. And I'm not entirely sure
> > > > > about how to decipher the expected values from the driver.
> > > >
> > > > drivers/gpu/drm/rockchip_drm_vop.c (my memory of the filename was faulty
> > > > it seems). As for comparing to the expected rate, I guess the easiest
> > > > way would be to just insert a printk into vop_crtc_mode_fixup()
> > > > after the clk_round_rate call, outputting both the requested and
> > > > calculated rate and then looking that up in the dmesg.
> > >
> > > dmesg:
> > > vop_crtc_mode_fixup() mode->clock=65000000 adjusted_mode->clock=61538000
> > >
> > > Is the adjusted clock withing the reasonable range?
> >
> > sadly, I have no real clue. I can cope with the hardware-centric parts like
> > making encoders somehow work, but I'm way out of my depth when it comes
> > to all this display-mode-voodoo.
> >
> > >
> > > Additionally I've had a look at the libdrm modetest util, and it is reporting
> > > far fewer modes than what I would expect on my 4k monitor.
> > >
> > > As an added note, I have this board+monitor working using proprietary drivers,
> > > and up to 4k resolutions.
> >
> > non-standard resolutions are still a bit of a problem I think.
> > The vendor kernel (and also the CrOS kernel) does contain quite a number
> > of hacks to make that work. (hacking up plls and the clock-tree, making
> > it quite non-generic).
> >
> > But yes, it seems that you only get 3 modes? That are way to few I think.
> > My display at least manages to get its 1080p native resolution, but I'm
> > also in the bind of having only this one display, so cannot really test
> > the more non-standard (or higher resolution) stuff.
> >
> > Do you happen to have any other display you could attach to just compare
> > what happens?
> >
> >
>
> FWIW, I have a Samsung (old?) TV, and on the same board as Robert's,
> with the same kernel and rootfs, I don't have any issues.

could you also take a look at the timing both requested and real
clock rate?