diff options
author | Alan Stern <stern@rowland.harvard.edu> | 2011-03-25 11:46:27 -0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-04-13 16:24:06 -0700 |
commit | ee81b3e086c907a3347b15ef219a24fc8bf900f6 (patch) | |
tree | 6ab1d90bc0ab2282c86dc332e97edf8df60559c9 /drivers/usb/gadget/file_storage.c | |
parent | edf847decc4159128041d2a81f8d93e6eb567ecb (diff) | |
download | linux-ee81b3e086c907a3347b15ef219a24fc8bf900f6.tar.bz2 |
USB: g_file_storage: don't send padding when stall=n
This patch (as1455) removes the extra padding sent by g_file_storage
and g_mass_storage when the gadget wants to send less data than
requested by the host and isn't allowed to halt the bulk-IN endpoint.
Although the Bulk-Only Transport specification requires the padding to
be present, it isn't truly needed since the transfer will be terminated
by a short packet anyway. Furthermore, many existing devices don't
bother to send any padding.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-By: Michal Nazarewicz <mina86@mina86.com>
CC: Roger Quadros <roger.quadros@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/gadget/file_storage.c')
-rw-r--r-- | drivers/usb/gadget/file_storage.c | 53 |
1 files changed, 12 insertions, 41 deletions
diff --git a/drivers/usb/gadget/file_storage.c b/drivers/usb/gadget/file_storage.c index d04e0e6b019d..aebfb81f3ba4 100644 --- a/drivers/usb/gadget/file_storage.c +++ b/drivers/usb/gadget/file_storage.c @@ -1932,37 +1932,6 @@ static int wedge_bulk_in_endpoint(struct fsg_dev *fsg) return rc; } -static int pad_with_zeros(struct fsg_dev *fsg) -{ - struct fsg_buffhd *bh = fsg->next_buffhd_to_fill; - u32 nkeep = bh->inreq->length; - u32 nsend; - int rc; - - bh->state = BUF_STATE_EMPTY; // For the first iteration - fsg->usb_amount_left = nkeep + fsg->residue; - while (fsg->usb_amount_left > 0) { - - /* Wait for the next buffer to be free */ - while (bh->state != BUF_STATE_EMPTY) { - rc = sleep_thread(fsg); - if (rc) - return rc; - } - - nsend = min(fsg->usb_amount_left, (u32) mod_data.buflen); - memset(bh->buf + nkeep, 0, nsend - nkeep); - bh->inreq->length = nsend; - bh->inreq->zero = 0; - start_transfer(fsg, fsg->bulk_in, bh->inreq, - &bh->inreq_busy, &bh->state); - bh = fsg->next_buffhd_to_fill = bh->next; - fsg->usb_amount_left -= nsend; - nkeep = 0; - } - return 0; -} - static int throw_away_data(struct fsg_dev *fsg) { struct fsg_buffhd *bh; @@ -2066,18 +2035,20 @@ static int finish_reply(struct fsg_dev *fsg) } } - /* For Bulk-only, if we're allowed to stall then send the - * short packet and halt the bulk-in endpoint. If we can't - * stall, pad out the remaining data with 0's. */ + /* + * For Bulk-only, mark the end of the data with a short + * packet. If we are allowed to stall, halt the bulk-in + * endpoint. (Note: This violates the Bulk-Only Transport + * specification, which requires us to pad the data if we + * don't halt the endpoint. Presumably nobody will mind.) + */ else { - if (mod_data.can_stall) { - bh->inreq->zero = 1; - start_transfer(fsg, fsg->bulk_in, bh->inreq, - &bh->inreq_busy, &bh->state); - fsg->next_buffhd_to_fill = bh->next; + bh->inreq->zero = 1; + start_transfer(fsg, fsg->bulk_in, bh->inreq, + &bh->inreq_busy, &bh->state); + fsg->next_buffhd_to_fill = bh->next; + if (mod_data.can_stall) rc = halt_bulk_in_endpoint(fsg); - } else - rc = pad_with_zeros(fsg); } break; |