From 5503a42c94dfc823dd005818444deb8d5efd9a98 Mon Sep 17 00:00:00 2001 From: Sui Chen Date: Tue, 9 May 2017 07:47:22 -0500 Subject: [PATCH] ahci: Acer SA5-271 SSD Not Detected Fix commit 8bfd174312629866efa535193d9e563768ff4307 upstream. (Correction in this resend: fixed function name acer_sa5_271_workaround; fixed the always-true condition in the function; fixed description.) On the Acer Switch Alpha 12 (model number: SA5-271), the internal SSD may not get detected because the port_map and CAP.nr_ports combination causes the driver to skip the port that is actually connected to the SSD. More specifically, either all SATA ports are identified as DUMMY, or all ports get ``link down'' and never get up again. This problem occurs occasionally. When this problem occurs, CAP may hold a value of 0xC734FF00 or 0xC734FF01 and port_map may hold a value of 0x00 or 0x01. When this problem does not occur, CAP holds a value of 0xC734FF02 and port_map may hold a value of 0x07. Overriding the CAP value to 0xC734FF02 and port_map to 0x7 significantly reduces the occurrence of this problem. Link: https://bugzilla.kernel.org/attachment.cgi?id=253091 Signed-off-by: Sui Chen Tested-by: Damian Ivanov Signed-off-by: Tejun Heo [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- Reading git-format-patch failed