Re: sata suspend resume ...
From: Jeff Garzik
Date: Fri Apr 21 2006 - 17:36:31 EST
Hugh Dickins wrote:
--- 2.6.17-rc2/drivers/scsi/libata-core.c 2006-04-19 09:14:11.000000000 +0100
+++ linux/drivers/scsi/libata-core.c 2006-04-21 20:55:48.000000000 +0100
@@ -4288,6 +4288,7 @@ int ata_device_resume(struct ata_port *a
{
if (ap->flags & ATA_FLAG_SUSPENDED) {
ap->flags &= ~ATA_FLAG_SUSPENDED;
+ ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT);
ata_set_mode(ap);
}
This is helpful to narrow down the problem, but its a bit of a layering
violation. In the current code, all functions called by
ata_device_{suspend,resume}() are high level functions, which uses
ata_qc_issue/ata_qc_complete high level API to address the device.
In contrast, ata_busy_sleep() sticks its hands deep into the host state
machine, and gives the tree a good hard shake. :) Consider that
ata_busy_sleep() doesn't make sense for unusual cases like
ATA-over-ethernet (AoE), or other tunnelled ATA transports.
It may very well be that ata_busy_sleep() is the proper solution for
your hardware, but it isn't applicable to all hardware.
So you really want an ata_make_sure_bus_is_awake_and_working() called at
that location. ata_busy_sleep()'s purpose is to bring a PATA-like bus
to the bus-idle state. So, when working on suspend/resume, the software
needs to have points at which the bus state is controlled/queried/asserted.
Jeff
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