From: Maxime Ripard <maxime.ripard@free-electrons.com>
To: Marek Vasut <marex@denx.de>
Cc: Shawn Guo <shawn.guo@linaro.org>,
linux-arm-kernel@lists.infradead.org,
Fabio Estevam <fabio.estevam@freescale.com>,
Alexandre Belloni <alexandre.belloni@free-electrons.com>,
Thomas Petazzoni <thomas@free-electrons.com>,
Brian Lilly <brian@crystalfontz.com>,
Sascha Hauer <s.hauer@pengutronix.de>,
Florian Tobias Schandinat <FlorianSchandinat@gmx.de>,
linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RESEND] video: mxsfb: Fix colors display on lower color depth
Date: Mon, 22 Apr 2013 12:19:37 +0200 [thread overview]
Message-ID: <51750EB9.3020301@free-electrons.com> (raw)
In-Reply-To: <201304221116.18080.marex@denx.de>
Hi Marek,
Le 22/04/2013 11:16, Marek Vasut a écrit :
> Dear Maxime Ripard,
>
>> The current code always registers as a 32 bits display, and uses the
>> hardware to drop the MSB of each color to abjust to the interface width
>> used by the panel.
>>
>> This results on 18 bits (and probably 16 bits display as well) in colors
>> being displayed poorly, because the MSB are obviously the most important
>> bits for each color definition.
>>
>> The default controller behaviour when using an interface width smaller
>> than the color depth is to drop the LSBs of each color, which makes more
>> sense because you lose the least important part of the color definition.
>>
>> So, to fix the colors display, just get back to the default controller
>> behaviour.
>>
>> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
>
> Did you receive my latest email? Check M28EVK (imx28-m28evk.dts), it uses 18bit
> LCD and works without this patch I think.
Thanks for the pointer. You mentionned in your other mail that it was
wired on 24bits but that the screen is actually 18 bits. I went to
search for the schematics to look at the wirings to see what could
differ, but I couldn't find any for the M28EVK. Are they publicly available?
Thanks,
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
next prev parent reply other threads:[~2013-04-22 10:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-22 8:11 [PATCH RESEND] video: mxsfb: Fix colors display on lower color depth Maxime Ripard
2013-04-22 9:08 ` Juergen Beisert
2013-04-22 10:15 ` Maxime Ripard
2013-04-22 9:16 ` Marek Vasut
2013-04-22 10:19 ` Maxime Ripard [this message]
2013-04-22 14:30 ` Marek Vasut
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