linux-kernel - Re: [PATCH 2.6.19-rc1 update 2] drivers: add LCD support

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Date:	Thu, 12 Oct 2006 16:05:26 +0000
From:	"Miguel Ojeda" <maxextreme@...il.com>
To:	"Paulo Marques" <pmarques@...popie.com>
Cc:	akpm@...l.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2.6.19-rc1 update 2] drivers: add LCD support

Excuse me, also:

On 10/12/06, Paulo Marques <pmarques@...popie.com> wrote:
>
> Also, what do these "nop"'s do? Isn't there a way to read the "busy"
> status from the controller and just write as fast as possible?
>

I found another bug that "changes" randomly the "startline" value. I
spent a _lot_ of time checking what would be the smallest way to have
the work done without any problem.

If you remove 1 of the 2 nops (after _address()), you will get some
flickering on one of the controllers, about 15 times per minute. If
you remove both, the "evil" controller do worse things.

Really, I have been trying a lot of ways to improve it and find the
explanation of that weird changes, and the best algorithm I found it
the one I have sent. Dirty, but it works safely. I also tried with
different timings and delays, but they didn't work. The only way I
found is to make the LCD do such "nop" operations.
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