From: Anders Date: Thu, 2 Oct 2014 02:42:33 +0000 (-0700) Subject: jtag/drivers/libusb1_common: avoid device reset when reselecting configuration X-Git-Tag: v0.9.0-rc1~254 X-Git-Url: https://review.openocd.org/gitweb?p=openocd.git;a=commitdiff_plain;h=ca8f8e7e77ec2263044288e540c7276155155a48 jtag/drivers/libusb1_common: avoid device reset when reselecting configuration According to [1], we shouldn't reselect an already active configuration to avoid needless device reset. This is known to cause issues with e.g. LPC Link2 with JLink firmware. [1] http://libusb.sourceforge.net/api-1.0/caveats.html#configsel Change-Id: I3568ada77780a521548c450090db7173f8d0b2dd Signed-off-by: Paul Fertser Signed-off-by: Anders Oleson Reviewed-on: http://openocd.zylin.com/2288 Tested-by: jenkins Reviewed-by: Spencer Oliver --- diff --git a/src/jtag/drivers/libusb1_common.c b/src/jtag/drivers/libusb1_common.c index a29b2e9105..07d9f9512c 100644 --- a/src/jtag/drivers/libusb1_common.c +++ b/src/jtag/drivers/libusb1_common.c @@ -165,9 +165,21 @@ int jtag_libusb_set_configuration(jtag_libusb_device_handle *devh, int retCode = -99; struct libusb_config_descriptor *config = NULL; + int current_config = -1; - libusb_get_config_descriptor(udev, configuration, &config); - retCode = libusb_set_configuration(devh, config->bConfigurationValue); + retCode = libusb_get_configuration(devh, ¤t_config); + if (retCode != 0) + return retCode; + + retCode = libusb_get_config_descriptor(udev, configuration, &config); + if (retCode != 0 || config == NULL) + return retCode; + + /* Only change the configuration if it is not already set to the + same one. Otherwise this issues a lightweight reset and hangs + LPC-Link2 with JLink firmware. */ + if (current_config != config->bConfigurationValue) + retCode = libusb_set_configuration(devh, config->bConfigurationValue); libusb_free_config_descriptor(config);