From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mark Langsdorf , Tejun Heo Subject: [ 044/103] sata_highbank: increase retry count but shorten duration for Calxeda controller Date: Tue, 23 Jul 2013 15:25:55 -0700 Message-Id: <20130723220423.481440928@linuxfoundation.org> In-Reply-To: <20130723220418.532514378@linuxfoundation.org> References: <20130723220418.532514378@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mark Langsdorf commit ddfef5de3d716f77bad32dbbba6b280158dfd721 upstream. Increase the retry count for the hard reset function to 100 but shorten the time out period to 500 ms. See the comment for ahci_highbank_hardreset for the reasons why those vaulues were chosen. Signed-off-by: Mark Langsdorf Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- drivers/ata/sata_highbank.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) --- a/drivers/ata/sata_highbank.c +++ b/drivers/ata/sata_highbank.c @@ -196,10 +196,26 @@ static int highbank_initialize_phys(stru return 0; } +/* + * The Calxeda SATA phy intermittently fails to bring up a link with Gen3 + * Retrying the phy hard reset can work around the issue, but the drive + * may fail again. In less than 150 out of 15000 test runs, it took more + * than 10 tries for the link to be established (but never more than 35). + * Triple the maximum observed retry count to provide plenty of margin for + * rare events and to guarantee that the link is established. + * + * Also, the default 2 second time-out on a failed drive is too long in + * this situation. The uboot implementation of the same driver function + * uses a much shorter time-out period and never experiences a time out + * issue. Reducing the time-out to 500ms improves the responsiveness. + * The other timing constants were kept the same as the stock AHCI driver. + * This change was also tested 15000 times on 24 drives and none of them + * experienced a time out. + */ static int ahci_highbank_hardreset(struct ata_link *link, unsigned int *class, unsigned long deadline) { - const unsigned long *timing = sata_ehc_deb_timing(&link->eh_context); + static const unsigned long timing[] = { 5, 100, 500}; struct ata_port *ap = link->ap; struct ahci_port_priv *pp = ap->private_data; u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG; @@ -207,7 +223,7 @@ static int ahci_highbank_hardreset(struc bool online; u32 sstatus; int rc; - int retry = 10; + int retry = 100; ahci_stop_engine(ap);