usb-linux: introduce a usb_linux_alt_setting function
The next patch in this series introduces multiple ways to get the alt setting dependent upon usb_fs_type, it is cleaner to put this into its own function. Note that this patch also changes the assumed alt setting in case of an error getting the alt setting to be 0 (a sane default) rather then the interface numberwhich makes no sense. Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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usb-linux.c
40
usb-linux.c
@ -823,13 +823,35 @@ usbdevfs:
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return configuration;
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}
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static uint8_t usb_linux_get_alt_setting(USBHostDevice *s,
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uint8_t configuration, uint8_t interface)
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{
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uint8_t alt_setting;
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struct usb_ctrltransfer ct;
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int ret;
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ct.bRequestType = USB_DIR_IN | USB_RECIP_INTERFACE;
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ct.bRequest = USB_REQ_GET_INTERFACE;
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ct.wValue = 0;
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ct.wIndex = interface;
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ct.wLength = 1;
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ct.data = &alt_setting;
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ct.timeout = 50;
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ret = ioctl(s->fd, USBDEVFS_CONTROL, &ct);
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if (ret < 0) {
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/* Assume alt 0 on error */
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return 0;
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}
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return alt_setting;
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}
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/* returns 1 on problem encountered or 0 for success */
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static int usb_linux_update_endp_table(USBHostDevice *s)
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{
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uint8_t *descriptors;
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uint8_t devep, type, configuration, alt_interface;
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struct usb_ctrltransfer ct;
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int interface, ret, length, i;
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int interface, length, i;
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i = usb_linux_get_configuration(s);
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if (i < 0)
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@ -858,19 +880,7 @@ static int usb_linux_update_endp_table(USBHostDevice *s)
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}
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interface = descriptors[i + 2];
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ct.bRequestType = USB_DIR_IN | USB_RECIP_INTERFACE;
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ct.bRequest = USB_REQ_GET_INTERFACE;
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ct.wValue = 0;
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ct.wIndex = interface;
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ct.wLength = 1;
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ct.data = &alt_interface;
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ct.timeout = 50;
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ret = ioctl(s->fd, USBDEVFS_CONTROL, &ct);
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if (ret < 0) {
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alt_interface = interface;
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}
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alt_interface = usb_linux_get_alt_setting(s, configuration, interface);
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/* the current interface descriptor is the active interface
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* and has endpoints */
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