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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20100727162510.GB17099@n2100.arm.linux.org.uk>
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?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/