[PATCH] [resend] Re: 6175ddf06b6172046a329e3abfd9c901a43efd2e breaks matroxfb console

Ondrej Zary
2010-08-11T19:38:29Z

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@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