Hello Jacopo,
Thank you for getting back to me!
> From: linux-renesas-soc-owner@xxxxxxxxxxxxxxx <linux-renesas-soc-owner@xxxxxxxxxxxxxxx> On Behalf Of Jacopo Mondi
> Sent: 23 July 2019 11:30
> Subject: Re: [PATCH v3 10/10] [HACK] arm64: dts: renesas: ebisu: Enable LVDS dual-link operation
>
> HI Fabrizio,
>
> On Mon, Jul 22, 2019 at 11:27:26AM +0000, Fabrizio Castro wrote:
> > Hello Jacopo,
> >
> > > From: linux-renesas-soc-owner@xxxxxxxxxxxxxxx <linux-renesas-soc-owner@xxxxxxxxxxxxxxx> On Behalf Of Laurent Pinchart
> > > Sent: 28 May 2019 15:13
> > > Subject: [PATCH v3 10/10] [HACK] arm64: dts: renesas: ebisu: Enable LVDS dual-link operation
> > >
> > > Enable and connect the second LVDS encoder to the second LVDS input of
> > > the THC63LVD1024 for dual-link LVDS operation. This requires changing
> > > the default settings of SW45 and SW47 to OFF and ON respectively.
> > >
> > > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> > > Tested-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
> >
> > How did you test this patch on Ebisu (kernel branch, configuration, switches,etc.)?
> >
>
> I tested the branch provided by Laurent and mentioned in this cover
> letter.
>
> The branch is now rebased on v5.2-rc1 as you can see, I cannot tell at
> the time which one was the release tag on which it was based on, but I
> suspect 5.0 or either v4.20. Maye Laurent remembers it.
>
> > I tested both linux-next and drm/du/lvds/dual-link and they are not working for me.
> > The base configuration I am using is coming from arch/arm64/configs/defconfig from each respective branch, on top of that I am
> enabling the remaining bits and pieces.
> > I have tried the suggested configuration of the switches for this patch, basically nothing is happening. I have also tried reverting the
> changes made by this patch (on both branches), and of course I have reverted the selection for the switches as well, and even single-
> link doesn't work for me. Single-link support from the BSP version of the kernel (4.14.75-ltsi) works for me, that confirms the
> configuration of the switches I am using when testing single-link should be okay.
> >
> > If, in the single-link use case from drm/du/lvds/dual-link, I connect lvds1 to the vga-encoder in the DT (like for the BSP DT, but I can
> see from the schematics that ADV7123 is actually connected to DU, like the configuration in the DT upstream), then HDMI works as
> expected (most of the time).
> >
> > I wonder if for some reason we may end up using the wrong lvds encoder at times, or no encoder at all?
> >
> > Have you seen this problem? Am I missing something obvious here?
>
> The branch I tested at the time worked out the box, but now, I see
> several different problems, and this morning I ran severl tests. Here
> it is a summary:
>
> Laurent's drm/du/lvds/dual-link and drm/du/next are v5.2-rc1 based.
> I see an error which makes Ebisu fail to boot on those branches and
> plain v5.2 (both -rc1 and final v5.2)
>
> The issue is related to bd9571 which seems to be an MFD gpio expander:
>
> [ 2.748694] bd9571mwv 8-0030: Device: BD9571MWV rev. 4
> [ 28.754865] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
> [ 28.761094] rcu: 1-...0: (2 ticks this GP) idle=352/1/0x4000000000000000 softirq=45/46 fqs=3250
>
> sometimes it even fail when detecting the chip:
> i2c-sh_mobile e60b0000.i2c: Transfer request timed out │
> bd9571mwv 8-0030: Failed to read vendor code register (ret=-110)
>
> I managed to boot the board once with no error, so I wonder if it is
> not my board which has issues?
>
> Anyway, this seems unrelated to the lvds dual link mode, but prevents
> me from testing anything on v5.2. I wonder if you ever seen anything similar...
I have just retested plain v5.2 on the Ebisu board (I am using the 4D, which
version of Ebisu are you using?) and I don't seem to have that specific issue.
Also, this time around the single-link configuration is working out of the box,
which is interesting.
>
> So I went and tested v5.1. Plain v5.1 with SW45 and SW47 in their
> 'default' position gives me a working output with single mode.
>
> I then cherry-picked the patches from Laurent's drm/du/lvds/dual-link
> and applied on top of v5.1 and it seems like DU does not get probed
> there.
>
> To be sure I was testing the same patches I tested at the time I gave
> my tag to this series I manually applied the patches from this series
> (not the one in Laurent's tree, but the ones here sent) on top of v5.1
> and I got the same result, DU was not probed correctly.
>
> I had a look at diff in the encoder registration process between 5.0 and
> 5.2 and I don't see much differences, so I suspect it might be some
> config option I have missed as well?
>
> Could you be a bit more precise on which tools are you using for
> testing and which failures you see? Are those the same I see here?
Even in my case DU doesn't get probed correctly either, rcar_du_probe
gets called into a couple of times, and both times it returns -EPROBE_DEFER.
I am using kms-tests at the moment.
>
> I'm testing using kms-tests or kmsxx alternatively, and made sure the
> DU driver was loaded (or not) with modeprint from drm's modetest
> suite. Basically, everything is mentioned here:
> uttps://elinux.org/R-Car/Devices#DU
>
> I could start reporting the v5.2 failure on Ebisu if you confirm me
> you see the same on your side, then trying to get to the bottom of the
> DU/lvds issue.
I am looking into dual-link support for RZ/G2E, and that's why I am interested
in seeing dual-link working on Ebisu. I am going to have a deeper look into
what's happening on Ebisu now that I know that you are having similar troubles
(besides bd9571mwv), but I may have more questions soon for you if you don't
mind?
Thanks,
Fab
>
> Thanks
> j
>
> >
> > Thanks,
> > Fab
> >
> > > ---
> > > .../arm64/boot/dts/renesas/r8a77990-ebisu.dts | 24 +++++++++++++------
> > > 1 file changed, 17 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/arch/arm64/boot/dts/renesas/r8a77990-ebisu.dts b/arch/arm64/boot/dts/renesas/r8a77990-ebisu.dts
> > > index c72772589953..988d82609f41 100644
> > > --- a/arch/arm64/boot/dts/renesas/r8a77990-ebisu.dts
> > > +++ b/arch/arm64/boot/dts/renesas/r8a77990-ebisu.dts
> > > @@ -93,11 +93,18 @@
> > >
> > > port@0 {
> > > reg = <0>;
> > > - thc63lvd1024_in: endpoint {
> > > + thc63lvd1024_in0: endpoint {
> > > remote-endpoint = <&lvds0_out>;
> > > };
> > > };
> > >
> > > + port@1 {
> > > + reg = <1>;
> > > + thc63lvd1024_in1: endpoint {
> > > + remote-endpoint = <&lvds1_out>;
> > > + };
> > > + };
> > > +
> > > port@2 {
> > > reg = <2>;
> > > thc63lvd1024_out: endpoint {
> > > @@ -482,24 +489,27 @@
> > > ports {
> > > port@1 {
> > > lvds0_out: endpoint {
> > > - remote-endpoint = <&thc63lvd1024_in>;
> > > + remote-endpoint = <&thc63lvd1024_in0>;
> > > };
> > > };
> > > };
> > > };
> > >
> > > &lvds1 {
> > > - /*
> > > - * Even though the LVDS1 output is not connected, the encoder must be
> > > - * enabled to supply a pixel clock to the DU for the DPAD output when
> > > - * LVDS0 is in use.
> > > - */
> > > status = "okay";
> > >
> > > clocks = <&cpg CPG_MOD 727>,
> > > <&x13_clk>,
> > > <&extal_clk>;
> > > clock-names = "fck", "dclkin.0", "extal";
> > > +
> > > + ports {
> > > + port@1 {
> > > + lvds1_out: endpoint {
> > > + remote-endpoint = <&thc63lvd1024_in1>;
> > > + };
> > > + };
> > > + };
> > > };
> > >
> > > &ohci0 {
> > > --
> > > Regards,
> > >
> > > Laurent Pinchart
> >
