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| author | Robert Hancock <hancockr@shaw.ca> | 2007-02-20 01:42:30 +0100 |
|---|---|---|
| committer | Jeff Garzik <jeff@garzik.org> | 2007-02-21 10:58:18 +0100 |
| commit | 5e5c74a5e11d1e2a99d03132cc6c4455016db6c2 (patch) | |
| tree | 7de25ad9b898e9fea72cecd8cdf9916de2c5a090 | |
| parent | libata: Fix Cell SATA driver dependencies (diff) | |
| download | linux-5e5c74a5e11d1e2a99d03132cc6c4455016db6c2.tar.xz linux-5e5c74a5e11d1e2a99d03132cc6c4455016db6c2.zip | |
sata_nv: delay on switching between NCQ and non-NCQ commands
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>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
| -rw-r--r-- | drivers/ata/sata_nv.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/ata/sata_nv.c b/drivers/ata/sata_nv.c index f1fea96e90bd..b93e64d3fcf1 100644 --- a/drivers/ata/sata_nv.c +++ b/drivers/ata/sata_nv.c @@ -219,6 +219,7 @@ struct nv_adma_port_priv { void __iomem * gen_block; void __iomem * notifier_clear_block; u8 flags; + int last_issue_ncq; }; struct nv_host_priv { @@ -1260,6 +1261,7 @@ static unsigned int nv_adma_qc_issue(struct ata_queued_cmd *qc) { 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 @@ static unsigned int nv_adma_qc_issue(struct ata_queued_cmd *qc) /* 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); |