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authorBin Liu <b-liu@ti.com>2017-03-10 23:43:35 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-03-14 12:13:14 +0300
commit0090114d336a9604aa2d90bc83f20f7cd121b76c (patch)
tree8be0ecc372c8792e8a280cf26ff1c5605c942adf /drivers/usb/musb
parent3243367b209faed5c320a4e5f9a565ee2a2ba958 (diff)
downloadlinux-0090114d336a9604aa2d90bc83f20f7cd121b76c.tar.xz
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: a655f481d83d6 ("usb: musb: musb_cppi41: handle pre-mature TX complete interrupt") Cc: <stable@vger.kernel.org> #4.1+ Reported-by: Alexandre Bailon <abailon@baylibre.com> Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Tested-by: Alexandre Bailon <abailon@baylibre.com> Signed-off-by: Bin Liu <b-liu@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/musb')
-rw-r--r--drivers/usb/musb/musb_cppi41.c23
1 files changed, 21 insertions, 2 deletions
diff --git a/drivers/usb/musb/musb_cppi41.c b/drivers/usb/musb/musb_cppi41.c
index 00e272bfee39..355655f8a3fb 100644
--- a/drivers/usb/musb/musb_cppi41.c
+++ b/drivers/usb/musb/musb_cppi41.c
@@ -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)
- empty = musb_is_tx_fifo_empty(hw_ep);
+ 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);