Re: [PATCH 08/11] usb: xhci-mtk: update fs bus bandwidth by bw_budget_table
From: Ikjoon Jang <hidden>
Date: 2021-08-03 06:05:33
Also in:
linux-arm-kernel, linux-devicetree, linux-mediatek, lkml
Hi Chunfeng, On Fri, Jul 30, 2021 at 4:51 PM Chunfeng Yun [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Use @bw_budget_table[] to update fs bus bandwidth due to not all microframes consume @bw_cost_per_microframe, see setup_sch_info(). Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> --- drivers/usb/host/xhci-mtk-sch.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-)diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c index 0bb1a6295d64..10c0f0f6461f 100644 --- a/drivers/usb/host/xhci-mtk-sch.c +++ b/drivers/usb/host/xhci-mtk-sch.c@@ -458,8 +458,8 @@ static int check_fs_bus_bw(struct mu3h_sch_ep_info *sch_ep, int offset) * Compared with hs bus, no matter what ep type, * the hub will always delay one uframe to send data */ - for (j = 0; j < sch_ep->cs_count; j++) { - tmp = tt->fs_bus_bw[base + j] + sch_ep->bw_cost_per_microframe; + for (j = 0; j < sch_ep->num_budget_microframes; j++) { + tmp = tt->fs_bus_bw[base + j] + sch_ep->bw_budget_table[j]; if (tmp > FS_PAYLOAD_MAX) return -ESCH_BW_OVERFLOW; }@@ -534,21 +534,18 @@ static void update_sch_tt(struct mu3h_sch_ep_info *sch_ep, bool used) { struct mu3h_sch_tt *tt = sch_ep->sch_tt; u32 base, num_esit; - int bw_updated; int i, j; num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit; - if (used) - bw_updated = sch_ep->bw_cost_per_microframe; - else - bw_updated = -sch_ep->bw_cost_per_microframe; - for (i = 0; i < num_esit; i++) { base = sch_ep->offset + i * sch_ep->esit; - for (j = 0; j < sch_ep->cs_count; j++) - tt->fs_bus_bw[base + j] += bw_updated; + for (j = 0; j < sch_ep->num_budget_microframes; j++) + if (used) + tt->fs_bus_bw[base + j] += sch_ep->bw_budget_table[j]; + else + tt->fs_bus_bw[base + j] -= sch_ep->bw_budget_table[j];
I agree that xhci-mtk-sch still has more rooms for tt periodic bandwidth
but I think this approach could trigger a problem.
for example, if there are two endpoints scheduled in the same u-frame index,
* ep1out = iso 192bytes bw_budget_table[] = { 188, 188, 0, ...} --> y0
* ep2in = int 64bytes, bw_budget_table[] = { 0, 0, 64, ... } --> y0
(If this is possible allocation from this patch),
I guess xhci-mtk could have some problems on internal scheduling?
}
if (used)-- 2.18.0