LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: "Chunfeng Yun (云春峰)" <Chunfeng.Yun@mediatek.com>
To: "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-mediatek@lists.infradead.org" 
	<linux-mediatek@lists.infradead.org>,
	"ikjn@chromium.org" <ikjn@chromium.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"matthias.bgg@gmail.com" <matthias.bgg@gmail.com>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	"mathias.nyman@intel.com" <mathias.nyman@intel.com>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>
Subject: Re: [PATCH] usb: xhci-mtk: relax TT periodic bandwidth allocation
Date: Wed, 11 Aug 2021 07:09:48 +0000	[thread overview]
Message-ID: <269c9a997cb4d3362fc111ed1efe0bd7eb6ac817.camel@mediatek.com> (raw)
In-Reply-To: <20210805133937.1.Ia8174b875bc926c12ce427a5a1415dea31cc35ae@changeid>

On Thu, 2021-08-05 at 13:39 +0800, Ikjoon Jang wrote:
> Currently xhci-mtk needs software-managed bandwidth allocation for
> periodic endpoints, it allocates the microframe index for the first
> start-split packet for each endpoint. As this index allocation logic
> should avoid the conflicts with other full/low-speed periodic
> endpoints,
> it uses the worst case byte budgets on high-speed bus bandwidth
> For example, for an isochronos IN endpoint with 192 bytes budget,
> it will consume the whole 4 u-frames(188 * 4) while the actual
> full-speed bus budget should be just 192bytes.
> 
> This patch changes the low/full-speed bandwidth allocation logic
> to use "approximate" best case budget for lower speed bandwidth
> management. For the same endpoint from the above example, the
> approximate best case budget is now reduced to (188 * 2) bytes.
> 
> Without this patch, many usb audio headsets with 3 interfaces
> (audio input, audio output, and HID) cannot be configured
> on xhci-mtk.
> 
> Signed-off-by: Ikjoon Jang <ikjn@chromium.org>
> ---
> 
>  drivers/usb/host/xhci-mtk-sch.c | 20 +++++++++++++-------
>  1 file changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-
> mtk-sch.c
> index f9b4d27ce449..46cbf5d54f4f 100644
> --- a/drivers/usb/host/xhci-mtk-sch.c
> +++ b/drivers/usb/host/xhci-mtk-sch.c
> @@ -459,16 +459,17 @@ static int check_fs_bus_bw(struct
> mu3h_sch_ep_info *sch_ep, int offset)
>  	u32 num_esit, tmp;
>  	int base;
>  	int i, j;
> +	u8 uframes = DIV_ROUND_UP(sch_ep->maxpkt, FS_PAYLOAD_MAX);
>  
>  	num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
> +
> +	if (sch_ep->ep_type == INT_IN_EP || sch_ep->ep_type ==
> ISOC_IN_EP)
> +		offset++;
> +
>  	for (i = 0; i < num_esit; i++) {
>  		base = offset + i * sch_ep->esit;
>  
> -		/*
> -		 * 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++) {
> +		for (j = 0; j < uframes; j++) {
Please don't calculate new value, should use the value calculated by
check_sch_tt().
See usb2.0 spec Figure 11-64, sometime will use 2 extra CS.

>  			tmp = tt->fs_bus_bw[base + j] + sch_ep-
> >bw_cost_per_microframe;
>  			if (tmp > FS_PAYLOAD_MAX)
>  				return -ESCH_BW_OVERFLOW;
> @@ -546,6 +547,8 @@ static void update_sch_tt(struct mu3h_sch_ep_info
> *sch_ep, bool used)
>  	u32 base, num_esit;
>  	int bw_updated;
>  	int i, j;
> +	int offset = sch_ep->offset;
> +	u8 uframes = DIV_ROUND_UP(sch_ep->maxpkt, FS_PAYLOAD_MAX);
>  
>  	num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
>  
> @@ -554,10 +557,13 @@ static void update_sch_tt(struct
> mu3h_sch_ep_info *sch_ep, bool used)
>  	else
>  		bw_updated = -sch_ep->bw_cost_per_microframe;
>  
> +	if (sch_ep->ep_type == INT_IN_EP || sch_ep->ep_type ==
> ISOC_IN_EP)
> +		offset++;
> +
>  	for (i = 0; i < num_esit; i++) {
> -		base = sch_ep->offset + i * sch_ep->esit;
> +		base = offset + i * sch_ep->esit;
>  
> -		for (j = 0; j < sch_ep->cs_count; j++)
> +		for (j = 0; j < uframes; j++)
>  			tt->fs_bus_bw[base + j] += bw_updated;
>  	}
>  

      reply	other threads:[~2021-08-11  7:10 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-05  5:39 Ikjoon Jang
2021-08-11  7:09 ` Chunfeng Yun (云春峰) [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=269c9a997cb4d3362fc111ed1efe0bd7eb6ac817.camel@mediatek.com \
    --to=chunfeng.yun@mediatek.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=ikjn@chromium.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mediatek@lists.infradead.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=mathias.nyman@intel.com \
    --cc=matthias.bgg@gmail.com \
    --subject='Re: [PATCH] usb: xhci-mtk: relax TT periodic bandwidth allocation' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).