This is a note to let you know that I've just added the patch titled ahci: disabled FBS prior to issuing software reset to the 3.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ahci-disabled-fbs-prior-to-issuing-software-reset.patch and it can be found in the queue-3.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 89dafa20f3daab5b3e0c13d0068a28e8e64e2102 Mon Sep 17 00:00:00 2001 From: xiangliang yu <yxlraid@xxxxxxxxx> Date: Sun, 27 Oct 2013 08:03:04 -0400 Subject: ahci: disabled FBS prior to issuing software reset From: xiangliang yu <yxlraid@xxxxxxxxx> commit 89dafa20f3daab5b3e0c13d0068a28e8e64e2102 upstream. Tested with Marvell 88se9125, attached with one port mulitplier(5 ports) and one disk, we will get following boot log messages if using current code: ata8: SATA link up 6.0 Gbps (SStatus 133 SControl 330) ata8.15: Port Multiplier 1.2, 0x1b4b:0x9715 r160, 5 ports, feat 0x1/0x1f ahci 0000:03:00.0: FBS is enabled ata8.00: hard resetting link ata8.00: SATA link down (SStatus 0 SControl 330) ata8.01: hard resetting link ata8.01: SATA link down (SStatus 0 SControl 330) ata8.02: hard resetting link ata8.02: SATA link down (SStatus 0 SControl 330) ata8.03: hard resetting link ata8.03: SATA link up 6.0 Gbps (SStatus 133 SControl 133) ata8.04: hard resetting link ata8.04: failed to resume link (SControl 133) ata8.04: failed to read SCR 0 (Emask=0x40) ata8.04: failed to read SCR 0 (Emask=0x40) ata8.04: failed to read SCR 1 (Emask=0x40) ata8.04: failed to read SCR 0 (Emask=0x40) ata8.03: native sectors (2) is smaller than sectors (976773168) ata8.03: ATA-8: ST3500413AS, JC4B, max UDMA/133 ata8.03: 976773168 sectors, multi 0: LBA48 NCQ (depth 31/32) ata8.03: configured for UDMA/133 ata8.04: failed to IDENTIFY (I/O error, err_mask=0x100) ata8.15: hard resetting link ata8.15: SATA link up 6.0 Gbps (SStatus 133 SControl 330) ata8.15: Port Multiplier vendor mismatch '0x1b4b' != '0x133' ata8.15: PMP revalidation failed (errno=-19) ata8.15: hard resetting link ata8.15: SATA link up 6.0 Gbps (SStatus 133 SControl 330) ata8.15: Port Multiplier vendor mismatch '0x1b4b' != '0x133' ata8.15: PMP revalidation failed (errno=-19) ata8.15: limiting SATA link speed to 3.0 Gbps ata8.15: hard resetting link ata8.15: SATA link up 3.0 Gbps (SStatus 123 SControl 320) ata8.15: Port Multiplier vendor mismatch '0x1b4b' != '0x133' ata8.15: PMP revalidation failed (errno=-19) ata8.15: failed to recover PMP after 5 tries, giving up ata8.15: Port Multiplier detaching ata8.03: disabled ata8.00: disabled ata8: EH complete The reason is that current detection code doesn't follow AHCI spec: First,the port multiplier detection process look like this: ahci_hardreset(link, class, deadline) if (class == ATA_DEV_PMP) { sata_pmp_attach(dev) /* will enable FBS */ sata_pmp_init_links(ap, nr_ports); ata_for_each_link(link, ap, EDGE) { sata_std_hardreset(link, class, deadline); if (link_is_online) /* do soft reset */ ahci_softreset(link, class, deadline); } } But, according to chapter 9.3.9 in AHCI spec: Prior to issuing software reset, software shall clear PxCMD.ST to '0' and then clear PxFBS.EN to '0'. The patch test ok with kernel 3.11.1. tj: Patch white space contaminated, applied manually with trivial updates. Signed-off-by: Xiangliang Yu <yuxiangl@xxxxxxxxxxx> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/ata/libahci.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) --- a/drivers/ata/libahci.c +++ b/drivers/ata/libahci.c @@ -1266,9 +1266,11 @@ int ahci_do_softreset(struct ata_link *l { struct ata_port *ap = link->ap; struct ahci_host_priv *hpriv = ap->host->private_data; + struct ahci_port_priv *pp = ap->private_data; const char *reason = NULL; unsigned long now, msecs; struct ata_taskfile tf; + bool fbs_disabled = false; int rc; DPRINTK("ENTER\n"); @@ -1278,6 +1280,16 @@ int ahci_do_softreset(struct ata_link *l if (rc && rc != -EOPNOTSUPP) ata_link_warn(link, "failed to reset engine (errno=%d)\n", rc); + /* + * According to AHCI-1.2 9.3.9: if FBS is enable, software shall + * clear PxFBS.EN to '0' prior to issuing software reset to devices + * that is attached to port multiplier. + */ + if (!ata_is_host_link(link) && pp->fbs_enabled) { + ahci_disable_fbs(ap); + fbs_disabled = true; + } + ata_tf_init(link->device, &tf); /* issue the first D2H Register FIS */ @@ -1318,6 +1330,10 @@ int ahci_do_softreset(struct ata_link *l } else *class = ahci_dev_classify(ap); + /* re-enable FBS if disabled before */ + if (fbs_disabled) + ahci_enable_fbs(ap); + DPRINTK("EXIT, class=%u\n", *class); return 0; Patches currently in stable-queue which might be from yxlraid@xxxxxxxxx are queue-3.10/ahci-disabled-fbs-prior-to-issuing-software-reset.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html