From 14cd5f8e85e90c9dead2393377b9a2c23131e0ce Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Thu, 23 Mar 2006 15:07:25 -0500 Subject: [PATCH] USB: g_file_storage: add comment about buffer allocation This patch (as664) adds a comment to file_storage.c, noting that the driver is slightly non-portable because it assumes that a buffer allocated for a bulk-in endpoint will also be useable for a bulk-out endpoint. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/file_storage.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'drivers/usb/gadget') diff --git a/drivers/usb/gadget/file_storage.c b/drivers/usb/gadget/file_storage.c index eb2821542b7..b6d920f349e 100644 --- a/drivers/usb/gadget/file_storage.c +++ b/drivers/usb/gadget/file_storage.c @@ -71,6 +71,12 @@ * requirement amounts to two 16K buffers, size configurable by a parameter. * Support is included for both full-speed and high-speed operation. * + * Note that the driver is slightly non-portable in that it assumes a + * single memory/DMA buffer will be useable for bulk-in, bulk-out, and + * interrupt-in endpoints. With most device controllers this isn't an + * issue, but there may be some with hardware restrictions that prevent + * a buffer from being used by more than one endpoint. + * * Module options: * * file=filename[,filename...] @@ -3956,6 +3962,9 @@ static int __init fsg_bind(struct usb_gadget *gadget) for (i = 0; i < NUM_BUFFERS; ++i) { struct fsg_buffhd *bh = &fsg->buffhds[i]; + /* Allocate for the bulk-in endpoint. We assume that + * the buffer will also work with the bulk-out (and + * interrupt-in) endpoint. */ bh->buf = usb_ep_alloc_buffer(fsg->bulk_in, mod_data.buflen, &bh->dma, GFP_KERNEL); if (!bh->buf) -- cgit v1.2.3