From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=35645 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PM2kv-0005ns-LL for qemu-devel@nongnu.org; Fri, 26 Nov 2010 13:10:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PM2ku-0002AI-70 for qemu-devel@nongnu.org; Fri, 26 Nov 2010 13:10:45 -0500 Received: from mx1.redhat.com ([209.132.183.28]:8767) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PM2kt-00029y-W5 for qemu-devel@nongnu.org; Fri, 26 Nov 2010 13:10:44 -0500 From: Hans de Goede Date: Fri, 26 Nov 2010 19:13:18 +0100 Message-Id: <1290795203-2597-2-git-send-email-hdegoede@redhat.com> In-Reply-To: <1290795203-2597-1-git-send-email-hdegoede@redhat.com> References: <1290795203-2597-1-git-send-email-hdegoede@redhat.com> Subject: [Qemu-devel] [PATCH 2/7] usb-linux: Get the alt. setting from sysfs rather then asking the dev List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: spice-devel@lists.freedesktop.org, Gerd Hoffmann , Hans de Goede At least one device I have lies when receiving a USB_REQ_GET_INTERFACE, always returning 0 even if the alternate setting is different. This is likely caused because in practice this control message is never used as the operating system's usb stack knows which alternate setting it has told the device to get into, and thus this ctrl message does not get tested by device manufacturers. When usb_fs_type == USB_FS_SYS, the active alt. setting can be read directly from sysfs, which allows using this device through qemu's usb redirection. More in general it seems a good idea to not send needless control msg's to devices, esp. as the code in question is called every time a set_interface is done. Which happens multiple times during virtual machine startup, and when device drivers are activating the usb device. Signed-off-by: Hans de Goede --- usb-linux.c | 18 ++++++++++++++++++ 1 files changed, 18 insertions(+), 0 deletions(-) diff --git a/usb-linux.c b/usb-linux.c index a93f0e5..ddd7c67 100644 --- a/usb-linux.c +++ b/usb-linux.c @@ -829,6 +829,24 @@ static uint8_t usb_linux_get_alt_setting(USBHostDevice *s, struct usb_ctrltransfer ct; int ret; + if (usb_fs_type == USB_FS_SYS) { + char device_name[64], line[1024]; + int alt_setting; + + sprintf(device_name, "%d-%d:%d.%d", s->bus_num, s->devpath, + (int)configuration, (int)interface); + + if (!usb_host_read_file(line, sizeof(line), "bAlternateSetting", + device_name)) { + goto usbdevfs; + } + if (sscanf(line, "%d", &alt_setting) != 1) { + goto usbdevfs; + } + return alt_setting; + } + +usbdevfs: ct.bRequestType = USB_DIR_IN | USB_RECIP_INTERFACE; ct.bRequest = USB_REQ_GET_INTERFACE; ct.wValue = 0; -- 1.7.3.2