diff options
Diffstat (limited to 'drivers/usb/storage/scsiglue.c')
| -rw-r--r-- | drivers/usb/storage/scsiglue.c | 16 |
1 files changed, 2 insertions, 14 deletions
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c index 13f2c051dbf2..fd5398efce41 100644 --- a/drivers/usb/storage/scsiglue.c +++ b/drivers/usb/storage/scsiglue.c @@ -90,20 +90,8 @@ static int slave_alloc (struct scsi_device *sdev) sdev->inquiry_len = 36; /* - * USB has unusual DMA-alignment requirements: Although the - * starting address of each scatter-gather element doesn't matter, - * the length of each element except the last must be divisible - * by the Bulk maxpacket value. There's currently no way to - * express this by block-layer constraints, so we'll cop out - * and simply require addresses to be aligned at 512-byte - * boundaries. This is okay since most block I/O involves - * hardware sectors that are multiples of 512 bytes in length, - * and since host controllers up through USB 2.0 have maxpacket - * values no larger than 512. - * - * But it doesn't suffice for Wireless USB, where Bulk maxpacket - * values can be as large as 2048. To make that work properly - * will require changes to the block layer. + * Some host controllers may have alignment requirements. + * We'll play it safe by requiring 512-byte alignment always. */ blk_queue_update_dma_alignment(sdev->request_queue, (512 - 1)); |