Re: libata-acpi: allow _GTF on SATA, but disable on PATA for now

From: Jeff Garzik
Date: Sat Mar 10 2007 - 06:30:45 EST


Linux Kernel Mailing List wrote:
Gitweb: http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=df33c77e3981e71afc8727ee5c432ba1a1bba68c
Commit: df33c77e3981e71afc8727ee5c432ba1a1bba68c
Parent: 908e0a8a265fe8057604a9a30aec3f0be7bb5ebb
Author: Kristen Accardi <kristen.c.accardi@xxxxxxxxx>
AuthorDate: Fri Mar 9 18:15:33 2007 -0500
Committer: Len Brown <len.brown@xxxxxxxxx>
CommitDate: Fri Mar 9 18:15:33 2007 -0500

libata-acpi: allow _GTF on SATA, but disable on PATA for now
The ACPI specification states, and BIOS implementations depend on,
_STM being called before _GTF.
SATA does this, but PATA does not. So for now, simply
prevent execution of _GTF on PATA devices. Longer term we
should implement ACPI support for PATA devices in libata.
Signed-off-by: Kristen Accardi <kristen.c.accardi@xxxxxxxxx>
Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
---
drivers/ata/libata-acpi.c | 7 +++++++
1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/drivers/ata/libata-acpi.c b/drivers/ata/libata-acpi.c
index d14a48e..89aaf74 100644
--- a/drivers/ata/libata-acpi.c
+++ b/drivers/ata/libata-acpi.c
@@ -561,6 +561,13 @@ int ata_acpi_exec_tfs(struct ata_port *ap)
if (noacpi)
return 0;
+ /*
+ * TBD - implement PATA support. For now,
+ * we should not run GTF on PATA devices since some
+ * PATA require execution of GTM/STM before GTF.
+ */
+ if (!(ap->cbl == ATA_CBL_SATA))
+ return 0;
for (ix = 0; ix < ATA_MAX_DEVICES; ix++) {
if (!ata_dev_enabled(&ap->device[ix]))

Grumble!

This /really/ should have gone through me and linux-ide first.

Alan has been actively working on PATA ACPI, and we have been debugging ACPI issues as well. PLEASE coordinate with the maintainer, when touching code outside of drivers/acpi!

AFAICS this patch went in with zero appearance on LKML or another related list, until submission. This is /not/ how we do Linux development.

Jeff


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