pata_ali can't detect partitions

[gianluca <gianluca@sottospazio.it>]

[-- Attachment #1: Type: text/plain, Size: 1095 bytes --]

Hello,

yesterday I tried to install archlinux-i586 on a old computer I have.
It's a K6-3 with a ALI chipset.

I noticed that the system was able to find the disk as sda but could not
recognize the partitions on the drive. This happens with the 2.6.30-ARCH
kernel of the archlinux-i586 installer.

I noticed also that with an older kernel (2.6.28 IIRC) the system could
detect all the partitions.

So yesterday I had some spare time to try to bisect the problem with git
bisect. The result of the bisection was the following commit:

commit 1b2c357c301b76118973763e886d9f70a7f50f7e
pata_ali: force initialise a few bits

I tried to backout the commit but that didn't succeed. So I looked carefully
at the diff and I came out with the attached patch which seems to fix the
problem (at least now the kernel detects the partitions correctly).

Since I saw that the above commit is fixing some real bugs (sunblade related)
I don't know whether the attached patch is right or is backing out the
intended fix. All I know is that it works for me and for this reason I'm
reporting it.

Thanks,
Gianluca

[-- Attachment #2: pata_ali.patch --]
[-- Type: text/x-diff, Size: 488 bytes --]

--- linux-2.6.31/drivers/ata/pata_ali.c.orig	2009-11-08 19:01:14.000000000 +0100
+++ linux-2.6.31/drivers/ata/pata_ali.c	2009-11-09 08:30:42.000000000 +0100
@@ -453,7 +453,7 @@
 			/* Clear CD-ROM DMA write bit */
 			tmp &= 0x7F;
 		/* Cable and UDMA */
-		pci_write_config_byte(pdev, 0x4B, tmp | 0x09);
+		pci_write_config_byte(pdev, 0x4B, tmp | 0x08);
 		/*
 		 * CD_ROM DMA on (0x53 bit 0). Enable this even if we want
 		 * to use PIO. 0x53 bit 1 (rev 20 only) - enable FIFO control