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Date: Fri, 30 Sep 2016 12:49:42 +0000
From: Karl Beldan <karl.beldan@gmail.com>
To: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Kevin Hilman <khilman@baylibre.com>,
        Michael Turquette <mturquette@baylibre.com>,
        Sekhar Nori <nsekhar@ti.com>, Rob Herring <robh+dt@kernel.org>,
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        Russell King <linux@armlinux.org.uk>,
        LKML <linux-kernel@vger.kernel.org>,
        arm-soc <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 4/6] ARM: dts: da850-lcdk: add support for 1024x768
 resolution
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On Fri, Sep 30, 2016 at 11:37:57AM +0200, Bartosz Golaszewski wrote:
> 2016-09-29 20:58 GMT+02:00 Karl Beldan <karl.beldan@gmail.com>:
> > Hi,
> >
> > On Thu, Sep 29, 2016 at 06:31:53PM +0200, Bartosz Golaszewski wrote:
> >> Add svga timings for 1024x768 resolution to the da850-lcdk
> >> device tree.
> >>
> >
> 
> [snip]
> 
> >
> > Why do you also call 1024x768 svga ?
> >
> 
> Thanks, should have been xga. will fix in v2.
> 
> > I don't think the LCDK can cope with this resolution at this frequency
> > (in terms of mem bandwidth), at least that's what I observed back in
> > August. If confirmed I think it is worth mentioning in the log at least,
> > but then I doubt adding this config would be useful.
> >
> 
> Thanks for the heads up. How would that manifest itself? This seems to
> work fine for me - I'm not getting any warnings on a simple system -
> maybe if I added some additional memory load it would complain.
> 

A mere dmesg > /dev/tty0 (or repeatedly cat-ting a file to /dev/tty0)
should suffice to make the issue visible and trigger FIFO underflows.

Regards, 
Karl