-/* Driver for USB Mass Storage compliant devices
+/*
+ * Driver for USB Mass Storage compliant devices
* SCSI layer glue code
*
* Current development and maintenance by:
#include "transport.h"
#include "protocol.h"
-/* Vendor IDs for companies that seem to include the READ CAPACITY bug
+/*
+ * Vendor IDs for companies that seem to include the READ CAPACITY bug
* in all their devices
*/
#define VENDOR_ID_NOKIA 0x0421
*/
sdev->inquiry_len = 36;
- /* USB has unusual DMA-alignment requirements: Although the
+ /*
+ * 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
{
struct us_data *us = host_to_us(sdev->host);
- /* Many devices have trouble transferring more than 32KB at a time,
+ /*
+ * Many devices have trouble transferring more than 32KB at a time,
* while others have trouble with more than 64K. At this time we
* are limiting both to 32K (64 sectores).
*/
blk_queue_max_hw_sectors(sdev->request_queue,
max_sectors);
} else if (sdev->type == TYPE_TAPE) {
- /* Tapes need much higher max_sector limits, so just
+ /*
+ * Tapes need much higher max_sector limits, so just
* raise it to the maximum possible (4 GB / 512) and
* let the queue segment size sort out the real limit.
*/
blk_queue_max_hw_sectors(sdev->request_queue, 0x7FFFFF);
+ } else if (us->pusb_dev->speed >= USB_SPEED_SUPER) {
+ /*
+ * USB3 devices will be limited to 2048 sectors. This gives us
+ * better throughput on most devices.
+ */
+ blk_queue_max_hw_sectors(sdev->request_queue, 2048);
}
- /* Some USB host controllers can't do DMA; they have to use PIO.
+ /*
+ * Some USB host controllers can't do DMA; they have to use PIO.
* They indicate this by setting their dma_mask to NULL. For
* such controllers we need to make sure the block layer sets
* up bounce buffers in addressable memory.
if (!us->pusb_dev->bus->controller->dma_mask)
blk_queue_bounce_limit(sdev->request_queue, BLK_BOUNCE_HIGH);
- /* We can't put these settings in slave_alloc() because that gets
+ /*
+ * We can't put these settings in slave_alloc() because that gets
* called before the device type is known. Consequently these
- * settings can't be overridden via the scsi devinfo mechanism. */
+ * settings can't be overridden via the scsi devinfo mechanism.
+ */
if (sdev->type == TYPE_DISK) {
- /* Some vendors seem to put the READ CAPACITY bug into
+ /*
+ * Some vendors seem to put the READ CAPACITY bug into
* all their devices -- primarily makers of cell phones
* and digital cameras. Since these devices always use
* flash media and can be expected to have an even number
* of sectors, we will always enable the CAPACITY_HEURISTICS
- * flag unless told otherwise. */
+ * flag unless told otherwise.
+ */
switch (le16_to_cpu(us->pusb_dev->descriptor.idVendor)) {
case VENDOR_ID_NOKIA:
case VENDOR_ID_NIKON:
break;
}
- /* Disk-type devices use MODE SENSE(6) if the protocol
+ /*
+ * Disk-type devices use MODE SENSE(6) if the protocol
* (SubClass) is Transparent SCSI, otherwise they use
- * MODE SENSE(10). */
+ * MODE SENSE(10).
+ */
if (us->subclass != USB_SC_SCSI && us->subclass != USB_SC_CYP_ATACB)
sdev->use_10_for_ms = 1;
- /* Many disks only accept MODE SENSE transfer lengths of
- * 192 bytes (that's what Windows uses). */
+ /*
+ *Many disks only accept MODE SENSE transfer lengths of
+ * 192 bytes (that's what Windows uses).
+ */
sdev->use_192_bytes_for_3f = 1;
- /* Some devices don't like MODE SENSE with page=0x3f,
+ /*
+ * Some devices don't like MODE SENSE with page=0x3f,
* which is the command used for checking if a device
* is write-protected. Now that we tell the sd driver
* to do a 192-byte transfer with this command the
* majority of devices work fine, but a few still can't
* handle it. The sd driver will simply assume those
- * devices are write-enabled. */
+ * devices are write-enabled.
+ */
if (us->fflags & US_FL_NO_WP_DETECT)
sdev->skip_ms_page_3f = 1;
- /* A number of devices have problems with MODE SENSE for
- * page x08, so we will skip it. */
+ /*
+ * A number of devices have problems with MODE SENSE for
+ * page x08, so we will skip it.
+ */
sdev->skip_ms_page_8 = 1;
/* Some devices don't handle VPD pages correctly */
/* Do not attempt to use WRITE SAME */
sdev->no_write_same = 1;
- /* Some disks return the total number of blocks in response
+ /*
+ * Some disks return the total number of blocks in response
* to READ CAPACITY rather than the highest block number.
- * If this device makes that mistake, tell the sd driver. */
+ * If this device makes that mistake, tell the sd driver.
+ */
if (us->fflags & US_FL_FIX_CAPACITY)
sdev->fix_capacity = 1;
- /* A few disks have two indistinguishable version, one of
+ /*
+ * A few disks have two indistinguishable version, one of
* which reports the correct capacity and the other does not.
- * The sd driver has to guess which is the case. */
+ * The sd driver has to guess which is the case.
+ */
if (us->fflags & US_FL_CAPACITY_HEURISTICS)
sdev->guess_capacity = 1;
if (sdev->scsi_level > SCSI_SPC_2)
us->fflags |= US_FL_SANE_SENSE;
- /* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
+ /*
+ * USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
* Hardware Error) when any low-level error occurs,
* recoverable or not. Setting this flag tells the SCSI
* midlayer to retry such commands, which frequently will
* succeed and fix the error. The worst this can lead to
- * is an occasional series of retries that will all fail. */
+ * is an occasional series of retries that will all fail.
+ */
sdev->retry_hwerror = 1;
- /* USB disks should allow restart. Some drives spin down
- * automatically, requiring a START-STOP UNIT command. */
+ /*
+ * USB disks should allow restart. Some drives spin down
+ * automatically, requiring a START-STOP UNIT command.
+ */
sdev->allow_restart = 1;
- /* Some USB cardreaders have trouble reading an sdcard's last
+ /*
+ * Some USB cardreaders have trouble reading an sdcard's last
* sector in a larger then 1 sector read, since the performance
- * impact is negligible we set this flag for all USB disks */
+ * impact is negligible we set this flag for all USB disks
+ */
sdev->last_sector_bug = 1;
- /* Enable last-sector hacks for single-target devices using
+ /*
+ * Enable last-sector hacks for single-target devices using
* the Bulk-only transport, unless we already know the
- * capacity will be decremented or is correct. */
+ * capacity will be decremented or is correct.
+ */
if (!(us->fflags & (US_FL_FIX_CAPACITY | US_FL_CAPACITY_OK |
US_FL_SCM_MULT_TARG)) &&
us->protocol == USB_PR_BULK)
} else {
- /* Non-disk-type devices don't need to blacklist any pages
+ /*
+ * Non-disk-type devices don't need to blacklist any pages
* or to force 192-byte transfer lengths for MODE SENSE.
- * But they do need to use MODE SENSE(10). */
+ * But they do need to use MODE SENSE(10).
+ */
sdev->use_10_for_ms = 1;
/* Some (fake) usb cdrom devices don't like READ_DISC_INFO */
sdev->no_read_disc_info = 1;
}
- /* The CB and CBI transports have no way to pass LUN values
+ /*
+ * The CB and CBI transports have no way to pass LUN values
* other than the bits in the second byte of a CDB. But those
* bits don't get set to the LUN value if the device reports
* scsi_level == 0 (UNKNOWN). Hence such devices must necessarily
sdev->scsi_level == SCSI_UNKNOWN)
us->max_lun = 0;
- /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
- * REMOVAL command, so suppress those commands. */
+ /*
+ * Some devices choke when they receive a PREVENT-ALLOW MEDIUM
+ * REMOVAL command, so suppress those commands.
+ */
if (us->fflags & US_FL_NOT_LOCKABLE)
sdev->lockable = 0;
- /* this is to satisfy the compiler, tho I don't think the
- * return code is ever checked anywhere. */
+ /*
+ * this is to satisfy the compiler, tho I don't think the
+ * return code is ever checked anywhere.
+ */
return 0;
}
usb_stor_dbg(us, "%s called\n", __func__);
- /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING
- * bits are protected by the host lock. */
+ /*
+ * us->srb together with the TIMED_OUT, RESETTING, and ABORTING
+ * bits are protected by the host lock.
+ */
scsi_lock(us_to_host(us));
/* Is this command still active? */
return FAILED;
}
- /* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if
+ /*
+ * Set the TIMED_OUT bit. Also set the ABORTING bit, but only if
* a device reset isn't already in progress (to avoid interfering
* with the reset). Note that we must retain the host lock while
* calling usb_stor_stop_transport(); otherwise it might interfere
- * with an auto-reset that begins as soon as we release the lock. */
+ * with an auto-reset that begins as soon as we release the lock.
+ */
set_bit(US_FLIDX_TIMED_OUT, &us->dflags);
if (!test_bit(US_FLIDX_RESETTING, &us->dflags)) {
set_bit(US_FLIDX_ABORTING, &us->dflags);
return SUCCESS;
}
-/* This invokes the transport reset mechanism to reset the state of the
- * device */
+/*
+ * This invokes the transport reset mechanism to reset the state of the
+ * device
+ */
static int device_reset(struct scsi_cmnd *srb)
{
struct us_data *us = host_to_us(srb->device->host);
return result < 0 ? FAILED : SUCCESS;
}
-/* Report a driver-initiated device reset to the SCSI layer.
+/*
+ * Report a driver-initiated device reset to the SCSI layer.
* Calling this for a SCSI-initiated reset is unnecessary but harmless.
- * The caller must own the SCSI host lock. */
+ * The caller must own the SCSI host lock.
+ */
void usb_stor_report_device_reset(struct us_data *us)
{
int i;
}
}
-/* Report a driver-initiated bus reset to the SCSI layer.
+/*
+ * Report a driver-initiated bus reset to the SCSI layer.
* Calling this for a SCSI-initiated reset is unnecessary but harmless.
- * The caller must not own the SCSI host lock. */
+ * The caller must not own the SCSI host lock.
+ */
void usb_stor_report_bus_reset(struct us_data *us)
{
struct Scsi_Host *host = us_to_host(us);
.target_alloc = target_alloc,
/* lots of sg segments can be handled */
- .sg_tablesize = SCSI_MAX_SG_CHAIN_SEGMENTS,
+ .sg_tablesize = SG_MAX_SEGMENTS,
- /* limit the total size of a transfer to 120 KB */
+
+ /*
+ * Limit the total size of a transfer to 120 KB.
+ *
+ * Some devices are known to choke with anything larger. It seems like
+ * the problem stems from the fact that original IDE controllers had
+ * only an 8-bit register to hold the number of sectors in one transfer
+ * and even those couldn't handle a full 256 sectors.
+ *
+ * Because we want to make sure we interoperate with as many devices as
+ * possible, we will maintain a 240 sector transfer size limit for USB
+ * Mass Storage devices.
+ *
+ * Tests show that other operating have similar limits with Microsoft
+ * Windows 7 limiting transfers to 128 sectors for both USB2 and USB3
+ * and Apple Mac OS X 10.11 limiting transfers to 256 sectors for USB2
+ * and 2048 for USB3 devices.
+ */
.max_sectors = 240,
- /* merge commands... this seems to help performance, but
+ /*
+ * merge commands... this seems to help performance, but
* periodically someone should test to see which setting is more
* optimal.
*/
projects / karo-tx-linux.git / blobdiff