From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH #upstraem-fixes] ata_piix: detect and clear spurious IRQs Date: Fri, 21 Nov 2008 13:13:06 +0900 Message-ID: <49263552.8090602@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from hera.kernel.org ([140.211.167.34]:50566 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753372AbYKUENS (ORCPT ); Thu, 20 Nov 2008 23:13:18 -0500 Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jeff Garzik , IDE/ATA development list The DMA_IRQ bit in the bmdma status register is always set when IDEIRQ is asserted allowing spurious IRQ detection. Detect spurious IRQs and clear them. This protects ata_piix against nobody-cared which gets reported not so rarely. Signed-off-by: Tejun Heo --- drivers/ata/ata_piix.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 53 insertions(+), 1 deletion(-) diff --git a/drivers/ata/ata_piix.c b/drivers/ata/ata_piix.c index 8e37be1..b438edc 100644 --- a/drivers/ata/ata_piix.c +++ b/drivers/ata/ata_piix.c @@ -922,6 +922,58 @@ static int piix_sidpr_scr_read(struct ata_link *link, return 0; } +static irqreturn_t piix_interrupt(int irq, void *dev_instance) +{ + struct ata_host *host = dev_instance; + unsigned int i; + unsigned int handled = 0; + unsigned long flags; + + spin_lock_irqsave(&host->lock, flags); + + for (i = 0; i < host->n_ports; i++) { + struct ata_port *ap = host->ports[i]; + struct ata_queued_cmd *qc; + u8 host_stat; + + if (ata_port_is_dummy(ap)) + continue; + + qc = ata_qc_from_tag(ap, ap->link.active_tag); + if (qc && !(qc->tf.flags & ATA_TFLAG_POLLING)) { + handled |= ata_sff_host_intr(ap, qc); + continue; + } + + /* + * Control reaches here if HSM is not expecting IRQ. + * If the controller is actually asserting IRQ line, + * this will lead to nobody cared. Fortuantely, + * DMA_INTR of PIIX is set whenever IDEIRQ is set so + * it can be used to detect spurious IRQs. As the + * driver is not expecting IRQ at all, clearing IRQ + * here won't lead to loss of IRQ event. + */ + if (unlikely(!ap->ioaddr.bmdma_addr)) + continue; + + host_stat = ap->ops->bmdma_status(ap); + if (!(host_stat & ATA_DMA_INTR)) + continue; + + if (printk_ratelimit()) + ata_port_printk(ap, KERN_INFO, + "clearing spurious IRQ\n"); + ap->ops->sff_check_status(ap); + ap->ops->sff_irq_clear(ap); + handled |= 1; + } + + spin_unlock_irqrestore(&host->lock, flags); + + return IRQ_RETVAL(handled); +} + static int piix_sidpr_scr_write(struct ata_link *link, unsigned int reg, u32 val) { @@ -1470,7 +1522,7 @@ static int __devinit piix_init_one(struct pci_dev *pdev, } pci_set_master(pdev); - return ata_pci_sff_activate_host(host, ata_sff_interrupt, &piix_sht); + return ata_pci_sff_activate_host(host, piix_interrupt, &piix_sht); } static int __init piix_init(void)