Commit 0090114d authored by Bin Liu's avatar Bin Liu Committed by Greg Kroah-Hartman

usb: musb: cppi41: don't check early-TX-interrupt for Isoch transfer

The CPPI 4.1 driver polls register to workaround the premature TX
interrupt issue, but it causes audio playback underrun when triggered in
Isoch transfers.

Isoch doesn't do back-to-back transfers, the TX should be done by the
time the next transfer is scheduled. So skip this polling workaround for
Isoch transfer.

Fixes: a655f481 ("usb: musb: musb_cppi41: handle pre-mature TX complete interrupt")
Cc: <stable@vger.kernel.org> #4.1+
Reported-by: default avatarAlexandre Bailon <abailon@baylibre.com>
Acked-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: default avatarAlexandre Bailon <abailon@baylibre.com>
Signed-off-by: default avatarBin Liu <b-liu@ti.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3243367b
......@@ -238,8 +238,27 @@ static void cppi41_dma_callback(void *private_data,
transferred < cppi41_channel->packet_sz)
cppi41_channel->prog_len = 0;
if (cppi41_channel->is_tx)
if (cppi41_channel->is_tx) {
u8 type;
if (is_host_active(musb))
type = hw_ep->out_qh->type;
else
type = hw_ep->ep_in.type;
if (type == USB_ENDPOINT_XFER_ISOC)
/*
* Don't use the early-TX-interrupt workaround below
* for Isoch transfter. Since Isoch are periodic
* transfer, by the time the next transfer is
* scheduled, the current one should be done already.
*
* This avoids audio playback underrun issue.
*/
empty = true;
else
empty = musb_is_tx_fifo_empty(hw_ep);
}
if (!cppi41_channel->is_tx || empty) {
cppi41_trans_done(cppi41_channel);
......
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