linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: dromede@gmail.com (Marko Katić)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC][PATCH] Disintegrate sharpsl_param.c
Date: Fri, 24 Aug 2012 14:53:15 +0200	[thread overview]
Message-ID: <CAHod+Gc8udMVChaezqte3dEns5E-udduwugL0o_VCYu=UCP9Tg@mail.gmail.com> (raw)
In-Reply-To: <20120824112536.GA19675@atrey.karlin.mff.cuni.cz>

On Fri, Aug 24, 2012 at 1:25 PM, Cyril Hrubis <metan@ucw.cz> wrote:
> Hi!
>> > > I recently tried running 3.6-rc2 kernel on my Sharp Zaurus C-1000. It
>> > > hanged almost immediately after uncompressing the kernel. I tracked the
>> > > problem down to a single line in arch/arm/common/sharpsl_param.c:
>> > >
>> > > memcpy(&sharpsl_param, (void *)PARAM_BASE, sizeof(struct sharpsl_param_info));
>> > >
>> > > Commenting out the line makes the kernel boot just fine. This left me
>> > > wondering whether sharpsl_param.c is actually needed. Here's a comment
>> > > from sharpsl_param.c that describes what sharpsl_param.c actually does:
>> >
>> > Sharp went to the trouble of saving these values into the hardware and
>> > passing them into the drivers. They're basically used by the LCD
>> > initialisation code from what I remember. I don't remember what the
>> > risks are of incorrect values.
>>
>> We were seeing strange flicker on LCD on some machines...? Particulary
>> metan's machine with wifi on did that. OTOH it looked like some kind
>> of DMA issue.
>
> Yes, the problems with my LCD are DMA related (too much DMA to wifi cf card
> causes timing issues on display refresh). When there is no network activity
> it's okay.
>
> And as far as I remeber there are some magic values needed for the LCD in order
> not to have distorted picture (blurred, etc.) There is a callibration program
> in the service menu that allows you to modify the values stored in the flash.
>
> I remeber Stanislav did some research on that (CCing).
>
> --
> metan

  reply	other threads:[~2012-08-24 12:53 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-22 17:27 [RFC][PATCH] Disintegrate sharpsl_param.c dromede at gmail.com
2012-08-22 19:19 ` Richard Purdie
2012-08-22 21:48   ` Marko Katić
2012-08-24 11:12   ` Pavel Machek
2012-08-24 11:25     ` Cyril Hrubis
2012-08-24 12:53       ` Marko Katić [this message]
2012-08-24 12:56         ` Marko Katić
  -- strict thread matches above, loose matches on Subject: below --
2012-08-24 22:24 Stanislav Brabec

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAHod+Gc8udMVChaezqte3dEns5E-udduwugL0o_VCYu=UCP9Tg@mail.gmail.com' \
    --to=dromede@gmail.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).