Hi Martin,
On 05/04/2015 08:54 PM, Martin K. Petersen wrote:
Some devices advertise support for the READ/WRITE LOG DMA EXT commands
but fail when we try to issue them. This can lead to queued TRIM being
unintentionally disabled since the relevant feature flag is located in a
general purpose log page.
Fall back to unqueued READ LOG EXT if the DMA variant fails while
reading a log page.
Have you seen both commands fail on any of the Samsung SSD 840 EVO
drives?
# dmesg | grep Samsung
[ 2.254443] ata10.00: ATA-9: Samsung SSD 840 EVO 1TB, EXT0BB6Q, max
UDMA/133
<dmesg output>
[ 2.254390] ata10.00: READ LOG DMA EXT failed, trying unqueued
[ 2.254441] ata10.00: failed to get NCQ Send/Recv Log Emask 0x1
<dmesg output>
(In this case it also failed READ LOG EXT)
This is linux-4.1.0-rc7 patched with the following from
http://git.kernel.org/cgit/linux/kernel/git/tj/libata.git/log/?h=for-4.2
libata: Allow NCQ TRIM to be enabled or disabled with a module parameter
libata: Expose TRIM capability in sysfs
libata: READ LOG DMA EXT support can be in either page 119 or 120
libata: Fall back to unqueued READ LOG EXT if the DMA variant fails
libata: Fix regression when the NCQ Send and Receive log page is absent
Thanks,
David
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
---
drivers/ata/libata-eh.c | 12 +++++++++++-
include/linux/libata.h | 1 +
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 07f41be38fbe..2893563d0537 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1507,13 +1507,17 @@ unsigned int ata_read_log_page(struct ata_device *dev, u8 log,
{
struct ata_taskfile tf;
unsigned int err_mask;
+ bool dma = false;
DPRINTK("read log page - log 0x%x, page 0x%x\n", log, page);
+retry:
ata_tf_init(dev, &tf);
- if (dev->dma_mode && ata_id_has_read_log_dma_ext(dev->id)) {
+ if (dev->dma_mode && ata_id_has_read_log_dma_ext(dev->id) &&
+ !(dev->horkage & ATA_HORKAGE_NO_NCQ_LOG)) {
tf.command = ATA_CMD_READ_LOG_DMA_EXT;
tf.protocol = ATA_PROT_DMA;
+ dma = true;
} else {
tf.command = ATA_CMD_READ_LOG_EXT;
tf.protocol = ATA_PROT_PIO;
@@ -1527,6 +1531,12 @@ unsigned int ata_read_log_page(struct ata_device *dev, u8 log,
err_mask = ata_exec_internal(dev, &tf, NULL, DMA_FROM_DEVICE,
buf, sectors * ATA_SECT_SIZE, 0);
+ if (err_mask && dma) {
+ dev->horkage |= ATA_HORKAGE_NO_NCQ_LOG;
+ ata_dev_warn(dev, "READ LOG DMA EXT failed, trying unqueued\n");
+ goto retry;
+ }
+
DPRINTK("EXIT, err_mask=%x\n", err_mask);
return err_mask;
}
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 8dad4a307bb8..c3ef58014b33 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -424,6 +424,7 @@ enum {
ATA_HORKAGE_NOLPM = (1 << 20), /* don't use LPM */
ATA_HORKAGE_WD_BROKEN_LPM = (1 << 21), /* some WDs have broken LPM */
ATA_HORKAGE_ZERO_AFTER_TRIM = (1 << 22),/* guarantees zero after trim */
+ ATA_HORKAGE_NO_NCQ_LOG = (1 << 23), /* don't use NCQ for log read */
/* DMA mask for user DMA control: User visible values; DO NOT
renumber */
--
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