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| author | Tejun Heo <tj@kernel.org> | 2011-05-14 12:28:04 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-14 10:45:59 -0700 |
| commit | 22fe9446e82f1fe4b59900db4599061384efb0ad (patch) | |
| tree | f5ad2181f1c9bcd8987b6f5b36c24e1f6b8d4140 /drivers/ata | |
| parent | ddb503b42960792f3be580f98959add669241a04 (diff) | |
| download | lwn-22fe9446e82f1fe4b59900db4599061384efb0ad.tar.gz lwn-22fe9446e82f1fe4b59900db4599061384efb0ad.zip | |
Revert "libata: ahci_start_engine compliant to AHCI spec"
This reverts commit 270dac35c26433d06a89150c51e75ca0181ca7e4.
The commits causes command timeouts on AC plug/unplug. It isn't yet
clear why. As the commit was for a single rather obscure controller,
revert the change for now.
The problem was reported and bisected by Gu Rui in bug#34692.
https://bugzilla.kernel.org/show_bug.cgi?id=34692
Also, reported by Rafael and Michael in the following thread.
http://thread.gmane.org/gmane.linux.kernel/1138771
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Gu Rui <chaos.proton@gmail.com>
Reported-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-by: Michael Leun <lkml20100708@newton.leun.net>
Cc: Jian Peng <jipeng2005@gmail.com>
Cc: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/ata')
| -rw-r--r-- | drivers/ata/libahci.c | 21 |
1 files changed, 0 insertions, 21 deletions
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c index ff9d832a163d..d38c40fe4ddb 100644 --- a/drivers/ata/libahci.c +++ b/drivers/ata/libahci.c @@ -561,27 +561,6 @@ void ahci_start_engine(struct ata_port *ap) { void __iomem *port_mmio = ahci_port_base(ap); u32 tmp; - u8 status; - - status = readl(port_mmio + PORT_TFDATA) & 0xFF; - - /* - * At end of section 10.1 of AHCI spec (rev 1.3), it states - * Software shall not set PxCMD.ST to 1 until it is determined - * that a functoinal device is present on the port as determined by - * PxTFD.STS.BSY=0, PxTFD.STS.DRQ=0 and PxSSTS.DET=3h - * - * Even though most AHCI host controllers work without this check, - * specific controller will fail under this condition - */ - if (status & (ATA_BUSY | ATA_DRQ)) - return; - else { - ahci_scr_read(&ap->link, SCR_STATUS, &tmp); - - if ((tmp & 0xf) != 0x3) - return; - } /* start DMA */ tmp = readl(port_mmio + PORT_CMD); |