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-rw-r--r--drivers/scsi/sd.c26
1 files changed, 25 insertions, 1 deletions
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 31b5273f4..4433b02c8 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3284,6 +3284,24 @@ static bool sd_validate_opt_xfer_size(struct scsi_disk *sdkp,
return true;
}
+static void sd_read_block_zero(struct scsi_disk *sdkp)
+{
+ unsigned int buf_len = sdkp->device->sector_size;
+ char *buffer, cmd[10] = { };
+
+ buffer = kmalloc(buf_len, GFP_KERNEL);
+ if (!buffer)
+ return;
+
+ cmd[0] = READ_10;
+ put_unaligned_be32(0, &cmd[2]); /* Logical block address 0 */
+ put_unaligned_be16(1, &cmd[7]); /* Transfer 1 logical block */
+
+ scsi_execute_cmd(sdkp->device, cmd, REQ_OP_DRV_IN, buffer, buf_len,
+ SD_TIMEOUT, sdkp->max_retries, NULL);
+ kfree(buffer);
+}
+
/**
* sd_revalidate_disk - called the first time a new disk is seen,
* performs disk spin up, read_capacity, etc.
@@ -3323,7 +3341,13 @@ static int sd_revalidate_disk(struct gendisk *disk)
*/
if (sdkp->media_present) {
sd_read_capacity(sdkp, buffer);
-
+ /*
+ * Some USB/UAS devices return generic values for mode pages
+ * until the media has been accessed. Trigger a READ operation
+ * to force the device to populate mode pages.
+ */
+ if (sdp->read_before_ms)
+ sd_read_block_zero(sdkp);
/*
* set the default to rotational. All non-rotational devices
* support the block characteristics VPD page, which will