From dfee02ac4bce6374c9769fe31f20794309341fa0 Mon Sep 17 00:00:00 2001 From: Guido Kiener Date: Wed, 12 Sep 2018 10:51:03 +0200 Subject: [PATCH] usb: usbtmc: Fix ioctl USBTMC_IOCTL_CLEAR Remove calculation of max_size (=wMaxPacketSize) and wrong condition (actual == max_size) in while loop. A device clear should always flush the complete Bulk-IN FIFO. Insert a sleep of 50 ms between subsequent CHECK_CLEAR_STATUS control requests to avoid stressing the instrument with repeated requests. Some instruments need time to cleanup internal I/O buffers. Polling and nonbraked requests slow down the response time of devices. Use USBTMC_BUFSIZE (4k) instead of USBTMC_SIZE_IOBUFFER (2k). Using USBTMC_SIZE_IOBUFFER is deprecated. Check only bit 0 (field bmClear) of the CHECK_CLEAR_STATUS response, since other bits are reserved and can change in future versions. Signed-off-by: Guido Kiener Reviewed-by: Steve Bayless Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/usbtmc.c | 46 +++++++++++++++----------------------- 1 file changed, 18 insertions(+), 28 deletions(-) diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c index 26a779d0c89b..11b2c8632d91 100644 --- a/drivers/usb/class/usbtmc.c +++ b/drivers/usb/class/usbtmc.c @@ -1632,20 +1632,17 @@ exit: static int usbtmc_ioctl_clear(struct usbtmc_device_data *data) { - struct usb_host_interface *current_setting; - struct usb_endpoint_descriptor *desc; struct device *dev; u8 *buffer; int rv; int n; int actual = 0; - int max_size; dev = &data->intf->dev; dev_dbg(dev, "Sending INITIATE_CLEAR request\n"); - buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL); + buffer = kmalloc(USBTMC_BUFSIZE, GFP_KERNEL); if (!buffer) return -ENOMEM; @@ -1653,7 +1650,7 @@ static int usbtmc_ioctl_clear(struct usbtmc_device_data *data) usb_rcvctrlpipe(data->usb_dev, 0), USBTMC_REQUEST_INITIATE_CLEAR, USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE, - 0, 0, buffer, 1, USBTMC_TIMEOUT); + 0, 0, buffer, 1, USB_CTRL_GET_TIMEOUT); if (rv < 0) { dev_err(dev, "usb_control_msg returned %d\n", rv); goto exit; @@ -1667,22 +1664,6 @@ static int usbtmc_ioctl_clear(struct usbtmc_device_data *data) goto exit; } - max_size = 0; - current_setting = data->intf->cur_altsetting; - for (n = 0; n < current_setting->desc.bNumEndpoints; n++) { - desc = ¤t_setting->endpoint[n].desc; - if (desc->bEndpointAddress == data->bulk_in) - max_size = usb_endpoint_maxp(desc); - } - - if (max_size == 0) { - dev_err(dev, "Couldn't get wMaxPacketSize\n"); - rv = -EPERM; - goto exit; - } - - dev_dbg(dev, "wMaxPacketSize is %d\n", max_size); - n = 0; usbtmc_clear_check_status: @@ -1693,7 +1674,7 @@ usbtmc_clear_check_status: usb_rcvctrlpipe(data->usb_dev, 0), USBTMC_REQUEST_CHECK_CLEAR_STATUS, USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE, - 0, 0, buffer, 2, USBTMC_TIMEOUT); + 0, 0, buffer, 2, USB_CTRL_GET_TIMEOUT); if (rv < 0) { dev_err(dev, "usb_control_msg returned %d\n", rv); goto exit; @@ -1710,15 +1691,19 @@ usbtmc_clear_check_status: goto exit; } - if (buffer[1] == 1) + if ((buffer[1] & 1) != 0) { do { dev_dbg(dev, "Reading from bulk in EP\n"); rv = usb_bulk_msg(data->usb_dev, usb_rcvbulkpipe(data->usb_dev, data->bulk_in), - buffer, USBTMC_SIZE_IOBUFFER, - &actual, USBTMC_TIMEOUT); + buffer, USBTMC_BUFSIZE, + &actual, USB_CTRL_GET_TIMEOUT); + + print_hex_dump_debug("usbtmc ", DUMP_PREFIX_NONE, + 16, 1, buffer, actual, true); + n++; if (rv < 0) { @@ -1726,10 +1711,15 @@ usbtmc_clear_check_status: rv); goto exit; } - } while ((actual == max_size) && + } while ((actual == USBTMC_BUFSIZE) && (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN)); + } else { + /* do not stress device with subsequent requests */ + msleep(50); + n++; + } - if (actual == max_size) { + if (n >= USBTMC_MAX_READS_TO_CLEAR_BULK_IN) { dev_err(dev, "Couldn't clear device buffer within %d cycles\n", USBTMC_MAX_READS_TO_CLEAR_BULK_IN); rv = -EPERM; @@ -1743,7 +1733,7 @@ usbtmc_clear_bulk_out_halt: rv = usb_clear_halt(data->usb_dev, usb_sndbulkpipe(data->usb_dev, data->bulk_out)); if (rv < 0) { - dev_err(dev, "usb_control_msg returned %d\n", rv); + dev_err(dev, "usb_clear_halt returned %d\n", rv); goto exit; } rv = 0; -- 2.30.2