Kuan Luo wrote:
Jeff Garzik wrote:
Kuan Luo wrote:
hi,
i saw the below changes from
http://git.kernel.org/?p=linux/kernel/git/jgarzik/libata-dev.g
it;a=commi
tdiff;h=5a5a9e1890b8260686218a68862d880daee1a817
[libata] sata_nv: Clean up ATA_FLAG_NCQ usage; bit test micro-opt
@@ -622,7 +622,9 @@ static const struct ata_port_info
nv_port_info[] =
{
/* SWNCQ */
{
.sht = &nv_swncq_sht,
- .flags = ATA_FLAG_SATA |
ATA_FLAG_NO_LEGACY,
+ .flags = ATA_FLAG_SATA |
ATA_FLAG_NO_LEGACY |
+ ATA_FLAG_NCQ,
+ .link_flags = ATA_LFLAG_HRST_TO_RESUME,
.pio_mask = NV_PIO_MASK,
.mwdma_mask = NV_MWDMA_MASK,
.udma_mask = NV_UDMA_MASK,
If swncq_enabled is set zero by user, nv_swncq_host_init
would not be
called .
Then ncq should be disabled and the libata shouldn't send ncq cmd.
I am not sure whether the ATA_FLAG_NCQ flag which is in
default set
makes libata send ncq cmd even when swncq_enable is 0?
nv_init_one
} else if (type == SWNCQ && swncq_enabled) {
dev_printk(KERN_NOTICE, &pdev->dev, "Using SWNCQ
mode\n");
nv_swncq_host_init(host);
Thanks for watching! Yes, that looks like a problem.
I still feel the flags usage I removed was problematic. A better
solution, I think, would be to do follow the ADMA example of
switching
the port_info type during early initialization:
if (type >= CK804 && adma_enabled) {
type = ADMA;
which in our case would result in
if (type == SWNCQ && !swncq_enabled)
type = GENERIC;
Or, if you prefer, we could take the opposite route, _not_
set SWNCQ in
the pci_device_id table, and instead do something like
if (type >= MCP65 && swncq_enabled)
type = SWNCQ;
(MCP65 is just a pulled-out-of-thin-air example)
Regards,
Jeff
1.The former method "type =GENERIC" cann't support hotplug in
mcp51-55-61.
'GENERIC' just an example; my apologies for the confusion.
2.As to the latter mehthod, do you mean we may set MCP65 in
pci_device_id table and add the extra variable
static const struct ata_port_operations nv_MCP65_ops ={...}.
Correct.
The main point was to fall back from SWNCQ to <something else>, if
!swncq_enabled, to avoid changing the ap->flags value after the port has
been allocated and initialized internally. And that switch must occur
prior to ata_pci_prepare_sff_host() call in nv_init_one().
Regards,
Jeff
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