[Intel-gfx] Missing DPPLL case on i7-1165G7

[Imre Deak]

On Tue, Jan 05, 2021 at 05:50:41AM +0000, Matthew Wilcox wrote:
> On Tue, Dec 29, 2020 at 04:41:31PM +0200, Imre Deak wrote:
> > Hi,
> > 
> > On Mon, Dec 21, 2020 at 04:07:58AM +0000, Matthew Wilcox wrote:
> > > 
> > > At boot,
> > > 
> > > [    2.787995] [drm:lspcon_init [i915]] *ERROR* Failed to probe lspcon
> > > [    2.788001] i915 0000:00:02.0: [drm] *ERROR* LSPCON init failed on port E
> > > [    2.790752] ------------[ cut here ]------------
> > > [    2.790753] Missing case (clock == 539440)
> > > [    2.790790] WARNING: CPU: 0 PID: 159 at drivers/gpu/drm/i915/display/intel_dpll_mgr.c:2967 icl_get_dplls+0x53a/0xa50 [i915]
> > 
> > the above warn looks to be due to a missing workaround fixed by
> > 
> > commit 0e2497e334de42dbaaee8e325241b5b5b34ede7e
> > Author: Imre Deak <imre.deak at intel.com>
> > Date:   Sat Oct 3 03:18:46 2020 +0300
> > 
> >     drm/i915/tgl: Fix Combo PHY DPLL fractional divider for 38.4MHz ref clock
> > 
> > in drm-tip. Could you give it a try?
> 
> I tried -rc2, which contains that commit, and the problem is gone.  Thank
> you!

Thanks for testing it, I'll send a patch for the 5.10 stable tree as
well.

> There is a different problem, which is that the brightness buttons
> (on F2 and F3 on this laptop) do not actually increase/decrease the
> brightness.  GNOME pops up a graphic that illustrates it is changing
> the brightness, but nothing actually changes.
> 
> xbacklight says "No outputs have backlight property" and using
> xrandr --output XWAYLAND0 --brightness 0.0001 doesn't change anything
> (for various different values, not just 0.0001).  Using xrandr --prop
> --verbose shows the reported value of "Brightness" changing, but nothing
> has changed on the screen.
> 
> I found
> /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight
> and tried setting 'brightness' in there to a few different values (100,
> 2000, 19200, 7000) and also nothing changed.
> 
> Any thoughts?

One possibility is that from the different backlight methods (DPCD,
direct PWM on a CPU pin) the driver selects the incorrect one. Could you
provide a log booting with drm.debug=0x1e adding it to a new ticket at

https://gitlab.freedesktop.org/drm/intel/-/issues/new?issue

or at least in a reply to this thread?

Adding Jani for further ideas.

--Imre