From 459ad68893a84fb0881e57919340b97edbbc3dc7 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 7 Dec 2007 12:46:23 +0900 Subject: libata: kill spurious NCQ completion detection Spurious NCQ completion detection implemented in ahci was incorrect. On AHCI receving and processing FISes and raising interrupts are not interlocked and spurious interrupts are expected. For example, if an interrupt occurs while interrupt handler is running and the running interrupt handler handles the event the new IRQ indicated, after IRQ handler finishes, it will be executed again because IRQ pending bit is set by the new interrupt but there won't be anything to process. Please read the following message for more information. http://article.gmane.org/gmane.linux.ide/26012 This patch... * Removes all spurious IRQ whining from ahci. Spurious NCQ completion detection was completely wrong. Spurious D2H Register FIS taught us that some early drives send spurious D2H Register FIS with I bit set while NCQ commands are in progress but none of recent drives does that and even the ones which show such behavior can do NCQ fine. * Kills all NCQ blacklist entries which were added because of spurious NCQ completions. I tracked down each commit and verified all removed ones are actually added because of spurious completions. WD740ADFD-00NLR1 wasn't deleted but moved upward because the drive not only had spurious NCQ completions but also is slow on sequential data transfers if NCQ is enabled. Maxtor 7V300F0 was added by 0e3dbc01d53940fe10e5a5cfec15ede3e929c918 from Alan Cox. I can only find evidences that the drive only had troubles with spuruious completions by searching the mailing list. This entry needs to be verified and removed if it doesn't have other NCQ related problems. Signed-off-by: Tejun Heo Cc: Alan Cox Signed-off-by: Jeff Garzik --- drivers/ata/ahci.c | 74 +++--------------------------------------------------- 1 file changed, 3 insertions(+), 71 deletions(-) (limited to 'drivers/ata/ahci.c') diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c index cb7853b7335d..54f38c21dd95 100644 --- a/drivers/ata/ahci.c +++ b/drivers/ata/ahci.c @@ -1640,7 +1640,7 @@ static void ahci_port_intr(struct ata_port *ap) struct ahci_host_priv *hpriv = ap->host->private_data; int resetting = !!(ap->pflags & ATA_PFLAG_RESETTING); u32 status, qc_active; - int rc, known_irq = 0; + int rc; status = readl(port_mmio + PORT_IRQ_STAT); writel(status, port_mmio + PORT_IRQ_STAT); @@ -1698,80 +1698,12 @@ static void ahci_port_intr(struct ata_port *ap) rc = ata_qc_complete_multiple(ap, qc_active, NULL); - /* If resetting, spurious or invalid completions are expected, - * return unconditionally. - */ - if (resetting) - return; - - if (rc > 0) - return; - if (rc < 0) { + /* while resetting, invalid completions are expected */ + if (unlikely(rc < 0 && !resetting)) { ehi->err_mask |= AC_ERR_HSM; ehi->action |= ATA_EH_SOFTRESET; ata_port_freeze(ap); - return; - } - - /* hmmm... a spurious interrupt */ - - /* if !NCQ, ignore. No modern ATA device has broken HSM - * implementation for non-NCQ commands. - */ - if (!ap->link.sactive) - return; - - if (status & PORT_IRQ_D2H_REG_FIS) { - if (!pp->ncq_saw_d2h) - ata_port_printk(ap, KERN_INFO, - "D2H reg with I during NCQ, " - "this message won't be printed again\n"); - pp->ncq_saw_d2h = 1; - known_irq = 1; - } - - if (status & PORT_IRQ_DMAS_FIS) { - if (!pp->ncq_saw_dmas) - ata_port_printk(ap, KERN_INFO, - "DMAS FIS during NCQ, " - "this message won't be printed again\n"); - pp->ncq_saw_dmas = 1; - known_irq = 1; } - - if (status & PORT_IRQ_SDB_FIS) { - const __le32 *f = pp->rx_fis + RX_FIS_SDB; - - if (le32_to_cpu(f[1])) { - /* SDB FIS containing spurious completions - * might be dangerous, whine and fail commands - * with HSM violation. EH will turn off NCQ - * after several such failures. - */ - ata_ehi_push_desc(ehi, - "spurious completions during NCQ " - "issue=0x%x SAct=0x%x FIS=%08x:%08x", - readl(port_mmio + PORT_CMD_ISSUE), - readl(port_mmio + PORT_SCR_ACT), - le32_to_cpu(f[0]), le32_to_cpu(f[1])); - ehi->err_mask |= AC_ERR_HSM; - ehi->action |= ATA_EH_SOFTRESET; - ata_port_freeze(ap); - } else { - if (!pp->ncq_saw_sdb) - ata_port_printk(ap, KERN_INFO, - "spurious SDB FIS %08x:%08x during NCQ, " - "this message won't be printed again\n", - le32_to_cpu(f[0]), le32_to_cpu(f[1])); - pp->ncq_saw_sdb = 1; - } - known_irq = 1; - } - - if (!known_irq) - ata_port_printk(ap, KERN_INFO, "spurious interrupt " - "(irq_stat 0x%x active_tag 0x%x sactive 0x%x)\n", - status, ap->link.active_tag, ap->link.sactive); } static void ahci_irq_clear(struct ata_port *ap) -- cgit v1.2.3