Mark Lord wrote:
I think this original patch still applies cleanly on at least 2.6.23-rc7. Drain up to 512 words from host/bridge FIFO on stuck DRQ HSM violation, rather than just getting stuck there forever. Signed-off-by: Mark Lord <mlord@xxxxxxxxx> --- --- old/drivers/ata/libata-sff.c 2007-09-28 09:29:22.000000000 -0400 +++ linux/drivers/ata/libata-sff.c 2007-09-28 09:39:44.000000000 -0400 @@ -420,6 +420,28 @@ ap->ops->irq_on(ap); } +static void ata_drain_fifo(struct ata_port *ap, struct ata_queued_cmd *qc) +{ + u8 stat = ata_chk_status(ap); + /* + * Try to clear stuck DRQ if necessary, + * by reading/discarding up to two sectors worth of data. + */ + if ((stat & ATA_DRQ) && (!qc || qc->dma_dir != DMA_TO_DEVICE)) { + unsigned int i; + unsigned int limit = qc ? qc->sect_size : ATA_SECT_SIZE; + + printk(KERN_WARNING "Draining up to %u words from data FIFO.\n", + limit); + for (i = 0; i < limit ; ++i) { + ioread16(ap->ioaddr.data_addr); + if (!(ata_chk_status(ap) & ATA_DRQ)) + break; + } + printk(KERN_WARNING "Drained %u/%u words.\n", i, limit); + } +} + /*** ata_bmdma_drive_eh - Perform EH with given methods for BMDMA controller* @ap: port to handle error for @@ -476,7 +498,7 @@ } ata_altstatus(ap); - ata_chk_status(ap); + ata_drain_fifo(ap, qc); ap->ops->irq_clear(ap); spin_unlock_irqrestore(ap->lock, flags);
applied, after hand-editing out the top of the message, so that it would not be copied into the kernel changelog
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