Messages in this thread Patch in this message | | | Date | Mon, 19 Feb 2007 18:42:30 -0600 | From | Robert Hancock <> | Subject | [PATCH] sata_nv: delay on switching between NCQ and non-NCQ commands |
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This patch appears to solve some problems with commands timing out in cases where an NCQ command is immediately followed by a non-NCQ command (or possibly vice versa). This is a rather ugly solution, but until we know more about why this is needed, this is about all we can do.
Signed-off-by: Robert Hancock <hancockr@shaw.ca>
--- linux-2.6.20-git6edit/drivers/ata/sata_nv.c.before_hacking 2007-02-15 18:19:13.000000000 -0600 +++ linux-2.6.20-git6edit/drivers/ata/sata_nv.c 2007-02-15 22:36:02.000000000 -0600 @@ -219,6 +219,7 @@ void __iomem * gen_block; void __iomem * notifier_clear_block; u8 flags; + int last_issue_ncq; }; struct nv_host_priv { @@ -1260,6 +1261,7 @@ { struct nv_adma_port_priv *pp = qc->ap->private_data; void __iomem *mmio = pp->ctl_block; + int curr_ncq = (qc->tf.protocol == ATA_PROT_NCQ); VPRINTK("ENTER\n"); @@ -1274,6 +1276,14 @@ /* write append register, command tag in lower 8 bits and (number of cpbs to append -1) in top 8 bits */ wmb(); + + if(curr_ncq != pp->last_issue_ncq) { + /* Seems to need some delay before switching between NCQ and non-NCQ + commands, else we get command timeouts and such. */ + udelay(20); + pp->last_issue_ncq = curr_ncq; + } + writew(qc->tag, mmio + NV_ADMA_APPEND); DPRINTK("Issued tag %u\n",qc->tag); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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