From: Andrey Shvetsov <andrey.shvetsov@xxxxxx>
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 <andrey.shvetsov@xxxxxx>
Signed-off-by: Christian Gromm <christian.gromm@xxxxxxxxxxxxx>
---
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 65211d1824b7..6e94ee2b4fb3 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) {
--
2.11.0
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