linux-kernel - Re: [PATCH] [resend] cyber2000fb: fix machine hang on module load

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Date:	Tue, 27 Jul 2010 17:25:11 +0100
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Ondrej Zary <linux@...nbow-software.org>
Cc:	linux-fbdev@...r.kernel.org,
	Kernel development list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] [resend] cyber2000fb: fix machine hang on module load

On Tue, Jul 27, 2010 at 03:29:20PM +0200, Ondrej Zary wrote:
> Hello,
> I was testing two CyberPro 2000 based PCI cards on x86 and the machine always
> hanged completely when the cyber2000fb module was loaded. It seems that the
> card hangs when some registers are accessed too quickly after writing RAMDAC
> control register. With this patch, both card work.
> 
> Add delay after RAMDAC control register write to prevent hangs on module load.

This one on the other hand I think is rather too heavy.

What might be better is to re-code the last register write to use
the x86 outb_p() stuff to slow it down, rather than using udelay().
Could you try something along those lines please?
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