From f500192890c7c6745a92b677f5f69e58a2d60715 Mon Sep 17 00:00:00 2001 From: Andrey Shvetsov Date: Fri, 7 Apr 2017 15:38:38 +0200 Subject: [PATCH] staging: most: usb: fix calculation of the extra_len The final size of the buffer used for the streaming transfer consists of the size for the user payload (buffer_size) and the size for the gaps needed by the controller (extra_len). The current implementation of the hdm_configure_channel() corrects the buffer size down to the next appropriate for the hardware value, that is the whole number of frames, but uses the old unaligned value to calculate the extra_len. Current patch fixes the described problem. Signed-off-by: Andrey Shvetsov Signed-off-by: Christian Gromm Signed-off-by: Greg Kroah-Hartman --- drivers/staging/most/hdm-usb/hdm_usb.c | 27 +++++++++------------------ 1 file changed, 9 insertions(+), 18 deletions(-) diff --git a/drivers/staging/most/hdm-usb/hdm_usb.c b/drivers/staging/most/hdm-usb/hdm_usb.c index 65211d1..6e94ee2 100644 --- a/drivers/staging/most/hdm-usb/hdm_usb.c +++ b/drivers/staging/most/hdm-usb/hdm_usb.c @@ -649,8 +649,6 @@ static int hdm_configure_channel(struct most_interface *iface, int channel, { unsigned int num_frames; unsigned int frame_size; - unsigned int temp_size; - unsigned int tail_space; struct most_dev *mdev = to_mdev(iface); struct device *dev = &mdev->usb_device->dev; @@ -685,7 +683,6 @@ static int hdm_configure_channel(struct most_interface *iface, int channel, } mdev->padding_active[channel] = true; - temp_size = conf->buffer_size; frame_size = get_stream_frame_size(conf); if (frame_size == 0 || frame_size > USB_MTU) { @@ -693,25 +690,19 @@ static int hdm_configure_channel(struct most_interface *iface, int channel, return -EINVAL; } + num_frames = conf->buffer_size / frame_size; + if (conf->buffer_size % frame_size) { - u16 tmp_val; - - tmp_val = conf->buffer_size / frame_size; - conf->buffer_size = tmp_val * frame_size; - dev_notice(dev, - "Channel %d - rounding buffer size to %d bytes, channel config says %d bytes\n", - channel, - conf->buffer_size, - temp_size); - } + u16 old_size = conf->buffer_size; - num_frames = conf->buffer_size / frame_size; - tail_space = num_frames * (USB_MTU - frame_size); - temp_size += tail_space; + conf->buffer_size = num_frames * frame_size; + dev_warn(dev, "%s: fixed buffer size (%d -> %d)\n", + mdev->suffix[channel], old_size, conf->buffer_size); + } /* calculate extra length to comply w/ HW padding */ - conf->extra_len = (DIV_ROUND_UP(temp_size, USB_MTU) * USB_MTU) - - conf->buffer_size; + conf->extra_len = num_frames * (USB_MTU - frame_size); + exit: mdev->conf[channel] = *conf; if (conf->data_type == MOST_CH_ASYNC) { -- 2.7.4