libata-acpi: implement dev->gtf_cache and evaluate _GTF right after _STM during resume
On certain implementations, _GTF evaluation depends on preceding _STM
and both can be pretty picky about the configuration. Using _GTM
result cached during controller initialization satisfies the most
neurotic _STM implementation. However, libata evaluates _GTF after
reset during device configuration and the hardware state can be
different from what _GTF expects and can cause evaluation failure.
This patch adds dev->gtf_cache and updates ata_dev_get_GTF() such that
it uses the cached value if available. Cache is cleared with a call
to ata_acpi_clear_gtf().
Because for SATA ACPI nodes _GTF must be evaluated after _SDD which
can't be done till IDENTIFY is complete, _GTF caching from
ata_acpi_on_resume() is used only for IDE ACPI nodes.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/include/linux/libata.h b/include/linux/libata.h
index ba84d8a..cb91280 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -498,6 +498,7 @@
struct scsi_device *sdev; /* attached SCSI device */
#ifdef CONFIG_ATA_ACPI
acpi_handle acpi_handle;
+ union acpi_object *gtf_cache;
#endif
/* n_sector is used as CLEAR_OFFSET, read comment above CLEAR_OFFSET */
u64 n_sectors; /* size of device, if ATA */