linux-kernel - Re: [Letux-kernel] BOG: commit 89c7cb1608ac3 ("of/device: Update dma_range_map only when dev has valid dma-ranges") seems to break Pinephone display or LCDC

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Message-ID: <20210206185956.64921c80@aktux>
Date:   Sat, 6 Feb 2021 18:59:56 +0100
From:   Andreas Kemnade <andreas@...nade.info>
To:     Paul Kocialkowski <paul.kocialkowski@...tlin.com>
Cc:     Discussions about the Letux Kernel <letux-kernel@...nphoenux.org>,
        "H. Nikolaus Schaller" <hns@...delico.com>,
        Rob Herring <robh@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Yong Wu <yong.wu@...iatek.com>,
        Robin Murphy <robin.murphy@....com>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [Letux-kernel] BOG: commit 89c7cb1608ac3 ("of/device: Update
 dma_range_map only when dev has valid dma-ranges") seems to break Pinephone
 display or LCDC

On Fri, 5 Feb 2021 16:10:18 +0100
Paul Kocialkowski <paul.kocialkowski@...tlin.com> wrote:

> Hey,
> 
> On Tue 02 Feb 21, 16:07, H. Nikolaus Schaller wrote:
> > Hi Paul,
> >   
> > > Am 02.02.2021 um 14:42 schrieb Paul Kocialkowski <paul.kocialkowski@...tlin.com>:
> > > 
> > > Hi Nikolaus,
> > > 
> > > On Tue 02 Feb 21, 11:50, H. Nikolaus Schaller wrote:  
> > >> Hi Paul,
> > >>   
> > >>> Am 02.02.2021 um 10:56 schrieb Paul Kocialkowski <paul.kocialkowski@...tlin.com>:
> > >>> 
> > >>> Hi Nikolaus,
> > >>> 
> > >>> On Tue 02 Feb 21, 10:18, H. Nikolaus Schaller wrote:  
> > >>>> Hi,
> > >>>> since v5.11-rc6 my Pinephone display shows some moiré pattern.
> > >>>> 
> > >>>> I did a bisect between v5.11-rc5 and v5.11-rc6 and it told me that
> > >>>> the commit mentioned in the subject is the reason.
> > >>>> 
> > >>>> Reverting it makes the display work again and re-reverting fail again.
> > >>>> 
> > >>>> IMHO it seems as if the display DMA of the pinephone (allwinner suni-a54)
> > >>>> got influenced and stopped to scan the framebuffer.
> > >>>> 
> > >>>> The only dma-ranges I could find are defined here:
> > >>>> 
> > >>>> 	arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
> > >>>> 
> > >>>> 	dma-ranges = <0x00000000 0x40000000 0xc0000000>;
> > >>>> 
> > >>>> but I can't tell if they are "valid" or not.
> > >>>> 
> > >>>> Any insights are welcome. And please direct to the right people/mailing lists
> > >>>> if they are missing.  
> > >>> 
> > >>> This may not be strictly the same thing, but is this patch in your tree:
> > >>> https://patchwork.kernel.org/project/linux-arm-kernel/patch/20210115175831.1184260-2-paul.kocialkowski@bootlin.com/
> > >>> 
> > >>> If not, it's worth a try to add it.  
> > >> 
> > >> No, it hasn't arrived in v5.11-rc6 (or linux-next) yet.
> > >> 
> > >> But it fixes the issue.  
> > > 
> > > Great! The patch should already be on its way to the next RC.  
> > 
> > Fine!
> >   
> > > 
> > > And nice to see you're active on Pinephone as well!  
> > 
> > I have a developer unit and the LetuxOS kernel already supports it a little. This is why I observed the issue with -rc6
> >   
> > > You might remember me from
> > > the Replicant project, as I've worked a bit on the GTA04 :)  
> > 
> > Sure, you are well remembered :)
> > 
> > I still have the dream to revitalize Replicant 4.2 for the GTA04 just for fun. I can already boot to Replicant touch screen with a v5.4 kernel. v5.10 fails when trying to spawn zygote...  
> 
> Oh I see! I think Android has made some significant progress is its ability
> to use mainline (4.2 was an early stage and I remember having to backport
> patches to use some mainline features back then).
> 
> Maybe it would be easier with Replicant 6, but you'd have to go through the
> device bringup phase again, which is never nice.
> 
well, we have done some experimental Replicant 6 images, but it is
unbeleavable slow. Do not know why. The bootanimation process(even
though there is no "animation") draws a lot of cpu power.

Regards,
Andreas