Messages in this thread Patch in this message | | | Date | Fri, 30 Mar 2007 14:03:57 -0700 | From | Greg KH <> | Subject | [patch 03/37] sata_nv: delay on switching between NCQ and non-NCQ commands |
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-stable review patch. If anyone has any objections, please let us know.
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From: Robert Hancock <hancockr@shaw.ca>
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>
--- drivers/ata/sata_nv.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- 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(str { 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(str /* 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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