This is a note to let you know that I've just added the patch titled
usb: xhci-mtk: add only one extra CS for FS/LS INTR
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-xhci-mtk-add-only-one-extra-cs-for-fs-ls-intr.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit ce1042669051cd3cc60ee4569c5bb72075821cb6
Author: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
Date: Mon Mar 8 10:51:53 2021 +0800
usb: xhci-mtk: add only one extra CS for FS/LS INTR
[ Upstream commit 1bf661daf6b084bc4d753f55b54f35dc98709685 ]
In USB2 Spec:
"11.18.5 TT Response Generation
In general, there will be two (or more) complete-split
transactions scheduled for a periodic endpoint.
However, for interrupt endpoints, the maximum size of
the full-/low-speed transaction guarantees that it can
never require more than two complete-split transactions.
Two complete-split transactions are only required
when the transaction spans a microframe boundary."
Due to the maxp is 64, and less then 188 (at most in one
microframe), seems never span boundary, so use only one CS
for FS/LS interrupt transfer, this will save some bandwidth.
Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/5b9ff09f53d23cf9e5c5437db4ffc18b798bf60c.1615170625.git.chunfeng.yun@xxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Stable-dep-of: 548011957d1d ("usb: xhci-mtk: relax TT periodic bandwidth allocation")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
index 450fa22b7dc7..59ba25ca018d 100644
--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -408,13 +408,11 @@ static int check_sch_tt(struct usb_device *udev,
{
struct mu3h_sch_tt *tt = sch_ep->sch_tt;
u32 extra_cs_count;
- u32 fs_budget_start;
u32 start_ss, last_ss;
u32 start_cs, last_cs;
int i;
start_ss = offset % 8;
- fs_budget_start = (start_ss + 1) % 8;
if (sch_ep->ep_type == ISOC_OUT_EP) {
last_ss = start_ss + sch_ep->cs_count - 1;
@@ -450,16 +448,14 @@ static int check_sch_tt(struct usb_device *udev,
if (sch_ep->ep_type == ISOC_IN_EP)
extra_cs_count = (last_cs == 7) ? 1 : 2;
else /* ep_type : INTR IN / INTR OUT */
- extra_cs_count = (fs_budget_start == 6) ? 1 : 2;
+ extra_cs_count = 1;
cs_count += extra_cs_count;
if (cs_count > 7)
cs_count = 7; /* HW limit */
- for (i = 0; i < cs_count + 2; i++) {
- if (test_bit(offset + i, tt->ss_bit_map))
- return -ERANGE;
- }
+ if (test_bit(offset, tt->ss_bit_map))
+ return -ERANGE;
sch_ep->cs_count = cs_count;
/* one for ss, the other for idle */
