diff options
| author | Robert Hancock <hancockr@shaw.ca> | 2007-03-22 12:39:04 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-04-06 03:43:11 -0700 |
| commit | 83b72f1c7cc4bfdb0958a2c1709c5a17ea10c7dd (patch) | |
| tree | 9cfd40fb99ff7cb63ca0bfb9b5b1d4f2c4bffc67 /drivers | |
| parent | 9f6a92b47b7580d35170712933f4eaab63d72238 (diff) | |
sata_nv: delay on switching between NCQ and non-NCQ commands
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.
[backport to 2.6.20 by Chuck Ebbert <cebbert@redhat.com>]
Signed-off-by: Robert Hancock <hancockr@shaw.ca>
Cc: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
| -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 f7a963eb1f0..91f24b1a2dc 100644 --- a/drivers/ata/sata_nv.c +++ b/drivers/ata/sata_nv.c @@ -214,6 +214,7 @@ struct nv_adma_port_priv { struct nv_adma_prd *aprd; dma_addr_t aprd_dma; u8 flags; + int last_issue_ncq; }; #define NV_ADMA_CHECK_INTR(GCTL, PORT) ((GCTL) & ( 1 << (19 + (12 * (PORT))))) @@ -1151,6 +1152,7 @@ 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 = nv_adma_ctl_block(qc->ap); + int curr_ncq = (qc->tf.protocol == ATA_PROT_NCQ); VPRINTK("ENTER\n"); @@ -1166,6 +1168,14 @@ 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); |