Messages in this thread Patch in this message | | | Date | Sat, 14 May 2011 12:28:04 +0200 | From | Tejun Heo <> | Subject | [PATCH v2.6.38-rc7] 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> --- As we're already in -rc7, I'm sending the revert patch to both Jeff and Linus.
Thank you.
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 ff9d832..d38c40f 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); -- 1.7.1
| |