4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Tejun Heo <t...@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 <t...@kernel.org> Reported-by: Andy Lutomirski <l...@amacapital.net> Link: http://lkml.kernel.org/g/calcetru7ymvxedhjaushohehdwifjgapdw--bkxsp0jmjkg...@mail.gmail.com Cc: Sergei Shtylyov <sergei.shtyl...@cogentembedded.com> Signed-off-by: Greg Kroah-Hartman <gre...@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);
