The {dma|pio}_mode sysfs files are incorrectly documented as having a list
of the supported DMA/PIO transfer modes, while the corresponding fields of
the *struct* ata_device hold the transfer mode IDs, not masks.
To match these docs, the {dma|pio}_mode (and even xfer_mode!) sysfs files
are handled by the ata_bitfield_name_match() macro which leads to reading
such kind of nonsense from them:
$ cat /sys/class/ata_device/dev3.0/pio_mode
XFER_UDMA_7, XFER_UDMA_6, XFER_UDMA_5, XFER_UDMA_4, XFER_MW_DMA_4,
XFER_PIO_6, XFER_PIO_5, XFER_PIO_4, XFER_PIO_3, XFER_PIO_2, XFER_PIO_1,
XFER_PIO_0
Using the correct ata_bitfield_name_search() macro fixes that:
$ cat /sys/class/ata_device/dev3.0/pio_mode
XFER_PIO_4
While fixing the file misdocumentation, somewhat reword the {dma|pio}_mode
file doc and add a note about being mostly useful for the PATA devices to
the xfer_mode file doc...
Fixes: d9027470b886 ("[libata] Add ATA transport class")
Signed-off-by: Sergey Shtylyov <s.shtylyov@xxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
This patch is against the 'master' branch of Damien's 'libata.git' repo.
Changes in version 2:
- added the Documentation/ABI/testing/sysfs-ata file, updating the patch
description accordingly.
Documentation/ABI/testing/sysfs-ata | 11 ++++++-----
drivers/ata/libata-transport.c | 2 +-
2 files changed, 7 insertions(+), 6 deletions(-)
Index: libata/Documentation/ABI/testing/sysfs-ata
===================================================================
--- libata.orig/Documentation/ABI/testing/sysfs-ata
+++ libata/Documentation/ABI/testing/sysfs-ata
@@ -107,13 +107,14 @@ Description:
described in ATA8 7.16 and 7.17. Only valid if
the device is not a PM.
- pio_mode: (RO) Transfer modes supported by the device when
- in PIO mode. Mostly used by PATA device.
+ pio_mode: (RO) PIO transfer mode used by the device.
+ Mostly used by the PATA devices.
- xfer_mode: (RO) Current transfer mode
+ xfer_mode: (RO) Current transfer mode. Mostly used by
+ the PATA devices.
- dma_mode: (RO) Transfer modes supported by the device when
- in DMA mode. Mostly used by PATA device.
+ dma_mode: (RO) DMA transfer mode used by the device.
+ Mostly used by the PATA devices.
class: (RO) Device class. Can be "ata" for disk,
"atapi" for packet device, "pmp" for PM, or
Index: libata/drivers/ata/libata-transport.c
===================================================================
--- libata.orig/drivers/ata/libata-transport.c
+++ libata/drivers/ata/libata-transport.c
@@ -196,7 +196,7 @@ static struct {
{ XFER_PIO_0, "XFER_PIO_0" },
{ XFER_PIO_SLOW, "XFER_PIO_SLOW" }
};
-ata_bitfield_name_match(xfer,ata_xfer_names)
+ata_bitfield_name_search(xfer, ata_xfer_names)
/*
* ATA Port attributes
