From e3943041a1d8869fb9d6779d49946e0a9d7dbff2 Mon Sep 17 00:00:00 2001 From: Antonio Ospite Date: Wed, 10 Jun 2015 12:38:21 +0200 Subject: [PATCH] am7xxx-modeswitch: set USB configuration following libusb documentation For the details see: http://libusb.sourceforge.net/api-1.0/caveats.html --- examples/am7xxx-modeswitch.c | 38 ++++++++++++++++++++++++++++++++++---- 1 file changed, 34 insertions(+), 4 deletions(-) diff --git a/examples/am7xxx-modeswitch.c b/examples/am7xxx-modeswitch.c index b431084..1230bd4 100644 --- a/examples/am7xxx-modeswitch.c +++ b/examples/am7xxx-modeswitch.c @@ -35,6 +35,7 @@ int main(void) { int ret; libusb_device_handle *usb_device; + int current_configuration; unsigned int len; int transferred; @@ -56,15 +57,26 @@ int main(void) goto out; } - ret = libusb_set_configuration(usb_device, AM7XXX_STORAGE_CONFIGURATION); + current_configuration = -1; + ret = libusb_get_configuration(usb_device, ¤t_configuration); if (ret < 0) { - fprintf(stderr, "libusb_set_configuration failed: %s\n", + fprintf(stderr, "libusb_get_configuration failed: %s\n", libusb_error_name(ret)); - fprintf(stderr, "Cannot set configuration %hhu\n", - AM7XXX_STORAGE_CONFIGURATION); goto out_libusb_close; } + if (current_configuration != AM7XXX_STORAGE_CONFIGURATION) { + ret = libusb_set_configuration(usb_device, + AM7XXX_STORAGE_CONFIGURATION); + if (ret < 0) { + fprintf(stderr, "libusb_set_configuration failed: %s\n", + libusb_error_name(ret)); + fprintf(stderr, "Cannot set configuration %hhu\n", + AM7XXX_STORAGE_CONFIGURATION); + goto out_libusb_close; + } + } + libusb_set_auto_detach_kernel_driver(usb_device, 1); ret = libusb_claim_interface(usb_device, AM7XXX_STORAGE_INTERFACE); @@ -76,6 +88,24 @@ int main(void) 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; + ret = libusb_get_configuration(usb_device, ¤t_configuration); + if (ret < 0) { + fprintf(stderr, "libusb_get_configuration after claim failed: %s\n", + libusb_error_name(ret)); + goto out_libusb_release_interface; + } + + if (current_configuration != AM7XXX_STORAGE_CONFIGURATION) { + fprintf(stderr, "libusb configuration changed (expected: %hhu, current: %hhu\n", + AM7XXX_STORAGE_CONFIGURATION, current_configuration); + ret = -EINVAL; + goto out_libusb_release_interface; + } + len = sizeof(switch_command); transferred = 0; ret = libusb_bulk_transfer(usb_device, AM7XXX_STORAGE_OUT_EP, -- 2.1.4