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authorTejun Heo <tj@kernel.org>2011-05-14 12:28:04 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-14 10:45:59 -0700
commit22fe9446e82f1fe4b59900db4599061384efb0ad (patch)
treef5ad2181f1c9bcd8987b6f5b36c24e1f6b8d4140 /drivers/ata
parentddb503b42960792f3be580f98959add669241a04 (diff)
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.c21
1 files changed, 0 insertions, 21 deletions
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index ff9d832a163..d38c40fe4dd 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);