From: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx> commit 8b13ea05117ffad4727b0971ed09122d5c91c4dc upstream. Currently uses the worst case byte budgets on FS/LS bus bandwidth, for example, for an isochronos IN endpoint with 192 bytes budget, it will consume the whole 5 uframes(188 * 5) while the actual FS bus budget should be just 192 bytes. It cause that many usb audio headsets with 3 interfaces (audio input, audio output, and HID) cannot be configured. To improve it, changes to use "approximate" best case budget for FS/LS bandwidth management. For the same endpoint from the above example, the approximate best case budget is now reduced to (188 * 2) bytes. Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx> Cc: stable <stable@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220819080556.32215-1-chunfeng.yun@xxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/host/xhci-mtk-sch.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) --- a/drivers/usb/host/xhci-mtk-sch.c +++ b/drivers/usb/host/xhci-mtk-sch.c @@ -425,7 +425,6 @@ static int check_fs_bus_bw(struct mu3h_s static int check_sch_tt(struct mu3h_sch_ep_info *sch_ep, u32 offset) { - u32 extra_cs_count; u32 start_ss, last_ss; u32 start_cs, last_cs; @@ -461,18 +460,12 @@ static int check_sch_tt(struct mu3h_sch_ if (last_cs > 7) return -ESCH_CS_OVERFLOW; - 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 = 1; - - cs_count += extra_cs_count; if (cs_count > 7) cs_count = 7; /* HW limit */ sch_ep->cs_count = cs_count; - /* one for ss, the other for idle */ - sch_ep->num_budget_microframes = cs_count + 2; + /* ss, idle are ignored */ + sch_ep->num_budget_microframes = cs_count; /* * if interval=1, maxp >752, num_budge_micoframe is larger
