diff options
| -rw-r--r-- | drivers/ata/libata-core.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index d4a7b8a96ecd..e7ea77cf6069 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -57,6 +57,7 @@ #include <linux/scatterlist.h> #include <linux/io.h> #include <linux/async.h> +#include <linux/log2.h> #include <scsi/scsi.h> #include <scsi/scsi_cmnd.h> #include <scsi/scsi_host.h> @@ -2389,6 +2390,7 @@ int ata_dev_configure(struct ata_device *dev) dev->cylinders = 0; dev->heads = 0; dev->sectors = 0; + dev->multi_count = 0; /* * common ATA, ATAPI feature tests @@ -2426,8 +2428,15 @@ int ata_dev_configure(struct ata_device *dev) dev->n_sectors = ata_id_n_sectors(id); - if (dev->id[59] & 0x100) - dev->multi_count = dev->id[59] & 0xff; + /* get current R/W Multiple count setting */ + if ((dev->id[47] >> 8) == 0x80 && (dev->id[59] & 0x100)) { + unsigned int max = dev->id[47] & 0xff; + unsigned int cnt = dev->id[59] & 0xff; + /* only recognize/allow powers of two here */ + if (is_power_of_2(max) && is_power_of_2(cnt)) + if (cnt <= max) + dev->multi_count = cnt; + } if (ata_id_has_lba(id)) { const char *lba_desc; |