Re: [PATCH 1/3] cyber2000fb: fix machine hang on module load

[Jeff Garzik <jeff@garzik.org>]

On 07/31/2010 05:25 PM, Russell King - ARM Linux wrote:
> On Sat, Jul 31, 2010 at 05:21:33PM -0400, Jeff Garzik wrote:
>> On 07/31/2010 04:55 PM, Ondrej Zary wrote:
>>> 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.
>>>
>>> Signed-off-by: Ondrej Zary<linux@rainbow-software.org>
>>>
>>> --- linux-2.6.35-rc2-orig/drivers/video/cyber2000fb.c	2010-06-06 05:43:24.000000000 +0200
>>> +++ linux-2.6.35-rc3/drivers/video/cyber2000fb.c	2010-07-27 23:12:37.000000000 +0200
>>> @@ -436,6 +436,8 @@ static void cyber2000fb_write_ramdac_ctr
>>>    	cyber2000fb_writeb(i | 4, 0x3cf, cfb);
>>>    	cyber2000fb_writeb(val, 0x3c6, cfb);
>>>    	cyber2000fb_writeb(i, 0x3cf, cfb);
>>> +	/* prevent card lock-up observed on x86 with CyberPro 2000 */
>>> +	cyber2000fb_readb(0x3cf, cfb);
>>>    }
>>
>> IIRC, cyber2000 is basically an S3 graphics chip.
>
> No such luck.  It's a proprietary Integraphics chip, mainly used in
> ARM Netwinders some 10 years ago.  It's completely different from the
> S3 chips such as Trio64.

Ah, I stand corrected.  Maybe that was cyberfb I was remembering...

	Jeff