[PATCH 4.3 167/200] libata: disable forced PORTS_IMPL for >= AHCI 1.3

From	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	[PATCH 4.3 167/200] libata: disable forced PORTS_IMPL for >= AHCI 1.3
Date	2016-02-15 00:50 +0100
Message-ID	<r2eAs-1fL-73@gated-at.bofh.it> (permalink)
References	<r2duF-zw-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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4.3-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tejun Heo <tj@kernel.org>

commit 566d1827df2ef0cbe921d3d6946ac3007b1a6938 upstream.

Some early controllers incorrectly reported zero ports in PORTS_IMPL
register and the ahci driver fabricates PORTS_IMPL from the number of
ports in those cases.  This hasn't mattered but with the new nvme
controllers there are cases where zero PORTS_IMPL is valid and should
be honored.

Disable the workaround for >= AHCI 1.3.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/g/CALCETrU7yMvXEDhjAUShoHEhDwifJGapdw--BKxsP0jmjKGmRw@mail.gmail.com
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/ata/libahci.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -495,8 +495,8 @@ void ahci_save_initial_config(struct dev
 		}
 	}
 
-	/* fabricate port_map from cap.nr_ports */
-	if (!port_map) {
+	/* fabricate port_map from cap.nr_ports for < AHCI 1.3 */
+	if (!port_map && vers < 0x10300) {
 		port_map = (1 << ahci_nr_ports(cap)) - 1;
 		dev_warn(dev, "forcing PORTS_IMPL to 0x%x\n", port_map);

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[PATCH 4.3 167/200] libata: disable forced PORTS_IMPL for >= AHCI 1.3 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-02-15 00:50 +0100

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