Re: [PATCH 1/3] RFT: drm/pl111: Support grayscale

From: Fabian Vogt <fabian@ritter-vogt•de>
To: Linus Walleij <linus.walleij@linaro•org>
Cc: Daniel Tang <dt.tangr@gmail•com>,
	"open list:DRM PANEL DRIVERS" <dri-devel@lists•freedesktop.org>,
	Linux ARM <linux-arm-kernel@lists•infradead.org>
Subject: Re: [PATCH 1/3] RFT: drm/pl111: Support grayscale
Date: Thu, 25 Jul 2019 21:26:41 +0200	[thread overview]
Message-ID: <12154694.e2V3OH3Rcx@linux-e202.suse.de> (raw)
In-Reply-To: <CACRpkdYAgLJ9asftN5EafeN5EVEyH_xHVdwjbecZqvgz-JJ98A@mail.gmail.com>

Hi,

Am Mittwoch, 24. Juli 2019, 14:33:06 CEST schrieb Linus Walleij:
> On Tue, Jul 23, 2019 at 5:19 PM Fabian Vogt <fabian@ritter-vogt•de> wrote:
> 
> > I gave the series a try (virtual CX and TP so far, will do on a real CX later):
> > OOPS with a nullptr deref during probe.
> > This diff which just moves some lines around fixes that and the LCD appears to
> > work properly.
> 
> OK I folded this into my patch, thanks!
> 
> > Once I verified the 24bit depth and clock speed config on HW as well, I can
> > give you my Tested-by, or would you prefer that I resubmit your series with the
> > fix below?
> 
> It's fine if you test it just with your patch as-is, I didn't change anything
> else.
> 
> I would be amazed if it "just works" now.

Indeed, you won't be. On a real CX the LCD displays shows content without
any other changes to the set, but has a ~3Hz pulsating effect scrolling from
the top to the bottom and the gray text changes color slightly.

Without the patchset applied everything looks perfectly.

I tried setting vrefresh to 20, fb_bpp to 16 and forcing an inverted panel
clock, but the pulsing didn't change.

Using the emulated CX I compared the contents of the registers and found
that only the IPC bit (which I tried to set, so that's likely not it) and
the interrupt registers have a different content.

Any idea?

Thanks,
Fabian

> Yours,
> Linus Walleij

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