Tejun Heo wrote:
Hello,
Mark Lord wrote:
I reported a very similar bug back a few releases ago.
Anyone who wants to try it themselves, can do this with hdparm-7.7 (from
sourceforge):
hdparm --drq-hsm-error /dev/sda
Whether or not it hangs the machine does depend upon exactly which SATA
LLD is used,
and what model/revision of drive is installed. But if it hangs for you
(eg. Tejun),
then you now have a way to reproduce a HSM error "on demand" for
testing. :)
Neat. Is this the FIFO-draining issue?
Yeah, that's the one. And I still patch my own kernels to
automatically drain up to 512 words from the FIFO when this happens.
Works like a charm. Patch below for demonstration purposes.
Signed-Off-By: Mark Lord <mlord@xxxxxxxxx>
---
--- linux/drivers/ata/libata-sff.c.orig 2007-04-26 12:02:46.000000000 -0400
+++ linux/drivers/ata/libata-sff.c 2007-04-29 08:29:27.000000000 -0400
@@ -413,6 +413,24 @@
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.
+ */
+ if ((stat & ATA_DRQ) && (!qc || qc->dma_dir != DMA_TO_DEVICE)) {
+ unsigned int i, limit = 512;
+ printk("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("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
@@ -469,7 +487,7 @@
}
ata_altstatus(ap);
- ata_chk_status(ap);
+ ata_drain_fifo(ap, qc);
ap->ops->irq_clear(ap);
spin_unlock_irqrestore(ap->lock, flags);
-
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