[PATCH 2.6.32 18/55] libata: disable forced PORTS_IMPL for >= AHCI 1.3

From: Willy Tarreau
Date: Fri Mar 04 2016 - 11:07:50 EST


2.6.32-longterm review patch. If anyone has any objections, please let me know.

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

From: Tejun Heo <tj@xxxxxxxxxx>

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@xxxxxxxxxx>
Reported-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/g/CALCETrU7yMvXEDhjAUShoHEhDwifJGapdw--BKxsP0jmjKGmRw@xxxxxxxxxxxxxx
Cc: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
[wt: file is drivers/ata/ahci.c in 2.6.32]
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
drivers/ata/ahci.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 6787aab..c075664 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -924,8 +924,8 @@ static void ahci_save_initial_config(struct pci_dev *pdev,
}
}

- /* 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_printk(KERN_WARNING, &pdev->dev,
"forcing PORTS_IMPL to 0x%x\n", port_map);
--
1.7.12.2.21.g234cd45.dirty