From 313d4a702aefeac3c8360141ae9037a8fdd47746 Mon Sep 17 00:00:00 2001 From: Antonio Ospite Date: Mon, 26 Jan 2015 00:00:25 +0100 Subject: [PATCH] am7xxx: use a saner approach when setting the USB configuration Follow the advices from http://libusb.sourceforge.net/api-1.0/caveats.html --- src/am7xxx.c | 31 ++++++++++++++++++++++++------- 1 file changed, 24 insertions(+), 7 deletions(-) diff --git a/src/am7xxx.c b/src/am7xxx.c index db7ca9a..321a193 100644 --- a/src/am7xxx.c +++ b/src/am7xxx.c @@ -708,6 +708,7 @@ static int open_device(am7xxx_context *ctx, am7xxx_device **dev) { int ret; + int current_configuration; *dev = find_device(ctx, device_index); if (*dev == NULL) { @@ -732,13 +733,17 @@ static int open_device(am7xxx_context *ctx, * to close it again before bailing out. */ - ret = libusb_set_configuration((*dev)->usb_device, - (*dev)->desc->configuration); - if (ret < 0) { - debug(ctx, "libusb_set_configuration failed\n"); - debug(ctx, "Cannot set configuration %hhu\n", - (*dev)->desc->configuration); - goto out_libusb_close; + current_configuration = -1; + libusb_get_configuration((*dev)->usb_device, ¤t_configuration); + if (current_configuration != (*dev)->desc->configuration) { + ret = libusb_set_configuration((*dev)->usb_device, + (*dev)->desc->configuration); + if (ret < 0) { + debug(ctx, "libusb_set_configuration failed\n"); + debug(ctx, "Cannot set configuration %hhu\n", + (*dev)->desc->configuration); + goto out_libusb_close; + } } ret = libusb_claim_interface((*dev)->usb_device, @@ -749,6 +754,18 @@ static int open_device(am7xxx_context *ctx, (*dev)->desc->interface_number); goto out_libusb_close; } + + /* Checking that the configuration has not changed, as suggested in + * http://libusb.sourceforge.net/api-1.0/caveats.html + */ + current_configuration = -1; + libusb_get_configuration((*dev)->usb_device, ¤t_configuration); + if (current_configuration != (*dev)->desc->configuration) { + debug(ctx, "libusb configuration changed\n"); + debug(ctx, "Cannot claim interface %hhu\n", + (*dev)->desc->interface_number); + goto out_libusb_close; + } out: return ret; -- 2.1.4