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From: H. Peter Anvin on 2 Aug 2010 17:50
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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From: Chris Rankin on 2 Aug 2010 20:10
> matroxfb (at least with Mystique and Mystique 220) stopped working
> in 2.6.34 - the screen is completely corrupted.

Interesting... I have just upgraded one of my old machines with a Matrox Millenium II card to 2.6.33.7, and have noticed that the matroxfb console has developed a slight wobble. (Think of a subtle "heat haze" / "one too many beers" kind of effect.)

Have any relevant changes been back-ported to 2.6.33.x-stable, please?

Cheers,
Chris



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From: Ondrej Zary on 3 Aug 2010 14:40
On Monday 02 August 2010 23:42:29 H. Peter Anvin wrote:
> 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.

Just tested the #else part on sparc and it seems to work fine - so I'm not going to touch (break) it.

> 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.

Thanks.

Here's v2 patch:


Fix incorrect use of memcpy_toio() in matroxfb that broke in 2.6.34.

Signed-off-by: Ondrej Zary <linux(a)rainbow-software.org>

--- 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 2010-08-03 18:13:46.000000000 +0200
@@ -151,13 +151,13 @@ static inline void mga_writel(vaddr_t va
static inline void mga_memcpy_toio(vaddr_t va, const void* src, int len) {
#if defined(__alpha__) || defined(__i386__) || defined(__x86_64__)
/*
- * memcpy_toio works for us if:
+ * iowrite32_rep works for us if:
* (1) Copies data as 32bit quantities, not byte after byte,
* (2) Performs LE ordered stores, and
* (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 >> 2);
#else
u_int32_t __iomem* addr = va.vaddr;



--
Ondrej Zary
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