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From: Ikjoon Jang <ikjn@chromium.org>
To: Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	Mathias Nyman <mathias.nyman@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	linux-usb@vger.kernel.org,
	"moderated list:ARM/Mediatek SoC support" 
	<linux-arm-kernel@lists.infradead.org>,
	"moderated list:ARM/Mediatek SoC support" 
	<linux-mediatek@lists.infradead.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>,
	Eddie Hung <eddie.hung@mediatek.com>
Subject: Re: [PATCH 08/11] usb: xhci-mtk: update fs bus bandwidth by bw_budget_table
Date: Tue, 3 Aug 2021 14:05:18 +0800	[thread overview]
Message-ID: <CAATdQgDWkohpzgr=z+uzro4m9Bd=v88DNnJ-M88-5-0annhH_w@mail.gmail.com> (raw)
In-Reply-To: <1627635002-24521-8-git-send-email-chunfeng.yun@mediatek.com>

Hi Chunfeng,

On Fri, Jul 30, 2021 at 4:51 PM Chunfeng Yun <chunfeng.yun@mediatek.com> wrote:
>
> 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
>

  reply	other threads:[~2021-08-03  6:05 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-30  8:49 [PATCH 01/11] dt-bindings: usb: mtk-xhci: add support property 'tpl-support' Chunfeng Yun
2021-07-30  8:49 ` [PATCH 02/11] dt-bindings: usb: mtk-xhci: add optional property to disable usb2 ports Chunfeng Yun
2021-08-06 20:41   ` Rob Herring
2021-08-11  8:12     ` Chunfeng Yun (云春峰)
2021-07-30  8:49 ` [PATCH 03/11] dt-bindings: usb: mtk-xhci: add compatible for mt8195 Chunfeng Yun
2021-08-06 20:43   ` Rob Herring
2021-08-11  8:02     ` Chunfeng Yun (云春峰)
2021-08-18 14:20       ` Rob Herring
2021-08-19 11:36         ` Chunfeng Yun (云春峰)
2021-07-30  8:49 ` [PATCH 04/11] usb: xhci-mtk: fix use-after-free of mtk->hcd Chunfeng Yun
2021-08-13  5:26   ` Ikjoon Jang
2021-07-30  8:49 ` [PATCH 05/11] usb: xhci-mtk: add support 'tpl-support' Chunfeng Yun
2021-07-30  8:49 ` [PATCH 06/11] usb: xhci-mtk: support option to disable usb2 ports Chunfeng Yun
2021-07-30  8:49 ` [PATCH 07/11] usb: xhci-mtk: fix issue of out-of-bounds array access Chunfeng Yun
2021-07-30  8:49 ` [PATCH 08/11] usb: xhci-mtk: update fs bus bandwidth by bw_budget_table Chunfeng Yun
2021-08-03  6:05   ` Ikjoon Jang [this message]
2021-08-04  5:19     ` Chunfeng Yun
2021-08-04 14:06       ` Ikjoon Jang
2021-08-10  1:45         ` Chunfeng Yun (云春峰)
2021-07-30  8:50 ` [PATCH 09/11] usb: xhci-mtk: check boundary before check tt Chunfeng Yun
2021-08-09  7:32   ` Ikjoon Jang
2021-08-11  8:18     ` Chunfeng Yun (云春峰)
2021-07-30  8:50 ` [PATCH 10/11] usb: xhci-mtk: add a member of num_esit Chunfeng Yun
2021-07-30  8:50 ` [PATCH 11/11] usb: xhci-mtk: modify the SOF/ITP interval for mt8195 Chunfeng Yun
2021-08-06 20:37 ` [PATCH 01/11] dt-bindings: usb: mtk-xhci: add support property 'tpl-support' Rob Herring
2021-08-11  7:54   ` Chunfeng Yun (云春峰)
2021-08-12  2:28   ` Chunfeng Yun (云春峰)

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