linux-kernel - Re: 6175ddf06b6172046a329e3abfd9c901a43efd2e breaks matroxfb console

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Message-ID: <4C573BC5.70007@zytor.com>
Date:	Mon, 02 Aug 2010 14:42:29 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Ondrej Zary <linux@...nbow-software.org>
CC:	brgerst@...il.com,
	Kernel development list <linux-kernel@...r.kernel.org>
Subject: Re: 6175ddf06b6172046a329e3abfd9c901a43efd2e breaks matroxfb console

On 08/02/2010 02:35 PM, Ondrej Zary wrote:
> 
> The patch below fixes it for me. Is it correct on all architectures?
> 
> --- linux-2.6.35-rc2/drivers/video/matrox/matroxfb_base.h	2010-06-06 05:43:24.000000000 +0200
> +++ linux-2.6.35-rc3/drivers/video/matrox/matroxfb_base.h	2010-08-02 23:31:34.000000000 +0200
> @@ -157,7 +157,7 @@ static inline void mga_memcpy_toio(vaddr
>  	 *  (3) It copes with unaligned source (destination is guaranteed to be page
>  	 *      aligned and length is guaranteed to be multiple of 4).
>  	 */
> -	memcpy_toio(va.vaddr, src, len);
> +	iowrite32_rep(va.vaddr, src, len);
>  #else
>          u_int32_t __iomem* addr = va.vaddr;
>  

I don't think so; in particular I don't *think* non-x86 architectures
will deal with the requirement that it handles an unaligned source.  As
such, the #if would still be necessary; the #else clause could be
replaced with a get_unaligned() ... iowrite32() loop.

The other thing to watch out for is that "len" passed to iowrite32_rep()
is a count of 32-bit words, whereas memcpy_toio() takes a byte count...
you need to >> 2 there.

	-hpa

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