From: Christian Lamparter Date: Fri, 10 Aug 2007 20:59:51 +0000 (-0700) Subject: ata_piix: disallow UDMA 133 on ICH5 & ICH7 X-Git-Tag: v2.6.24-rc1~1391^2~94 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2eb829e934abb10db36ddaacd82603c3cdd98b6d;p=pandora-kernel.git ata_piix: disallow UDMA 133 on ICH5 & ICH7 There is another outstanding issue with ata_piix.c. Intel has never officially supported anything faster than PATA 100MB/s. But, the ata_piix.c driver "define" the ICH5 & ICH7 as UDMA6 (aka 133MB/s) capable. [ Well, no one has probably noticed it before, because there is bug in do_pata_set_dmamode... Just look at libata_atapiix_enable_real_udma133.patch and you'll see what wrong with it. ] Here are Intel's datasheets for the affected chipsets: ICH5 Datasheet: http://www.intel.com/design/chipsets/datashts/252516.htm (See note on page 183: "... the ICH5 supports reads at the maximum rate of 100MB/s.") ICH7 Datasheet: http://www.intel.com/design/chipsets/datashts/307013.htm (See first note on page 190: "... the ICH7 supports reads at the maximum rate of 100MB/s.") They are two different ways to deal with it: - Either - 1. replace all ich_pata_133 with ich_pata_100. (libata_atapiix_disable_udma6.diff - diff from 2.6.22 ) - Or - 2. keep all ich_pata_133 and fix the bug in "do_pata_set_dmamode". (libata_atapiix_enable_real_udma133.patch - diff from 2.6.22) If there are any concerns about the safety of the patch patch: http://lkml.org/lkml/2007/7/6/292 (It was already tested by an Intel employee, but I guess a bit more user input is necessary here... ) This patch implements 1. Cc: Alan Cox Cc: Jeff Garzik Cc: Tejun Heo Signed-off-by: Christian Lamparter Signed-off-by: Andrew Morton Signed-off-by: Jeff Garzik --- Reading git-diff-tree failed