All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ikjoon Jang <ikjn@chromium.org>
To: "Chunfeng Yun (云春峰)" <Chunfeng.Yun@mediatek.com>
Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"matthias.bgg@gmail.com" <matthias.bgg@gmail.com>,
	"linux-mediatek@lists.infradead.org" 
	<linux-mediatek@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	"mathias.nyman@intel.com" <mathias.nyman@intel.com>
Subject: Re: [RFC PATCH] usb: xhci-mtk: handle bandwidth table rollover
Date: Thu, 12 Aug 2021 17:31:45 +0800	[thread overview]
Message-ID: <CAATdQgD1paUUmWhiLVq-+zq0V6=RTJw89ggk=R6cBUZO+5dB-Q@mail.gmail.com> (raw)
In-Reply-To: <7b48f4c132a8b4b3819282e961fbe8b3ed753069.camel@mediatek.com>

HI,

On Wed, Aug 11, 2021 at 5:02 PM Chunfeng Yun (云春峰)
<Chunfeng.Yun@mediatek.com> wrote:
>
> On Mon, 2021-08-09 at 17:42 +0800, Ikjoon Jang wrote:
> > On Mon, Aug 9, 2021 at 5:11 PM Greg Kroah-Hartman
> > <gregkh@linuxfoundation.org> wrote:
> > >
> > > On Mon, Aug 09, 2021 at 04:59:29PM +0800, Ikjoon Jang wrote:
> > > > xhci-mtk has 64 slots for periodic bandwidth calculations and
> > > > each
> > > > slot represents byte budgets on a microframe. When an endpoint's
> > > > allocation sits on the boundary of the table, byte budgets' slot
> > > > should be rolled over but the current implementation doesn't.
> > > >
> > > > This patch applies a 6 bits mask to the microframe index to
> > > > handle
> > > > its rollover 64 slots and prevent out-of-bounds array access.
> > > >
> > > > Signed-off-by: Ikjoon Jang <ikjn@chromium.org>
> > > > ---
> > > >
> > > >  drivers/usb/host/xhci-mtk-sch.c | 79 +++++++++----------------
> > > > --------
> > > >  drivers/usb/host/xhci-mtk.h     |  1 +
> > > >  2 files changed, 23 insertions(+), 57 deletions(-)
> > >
> > > Why is this "RFC"?  What needs to be addressed in this change
> > > before it
> > > can be accepted?
> >
> > sorry, I had to mention why this is RFC:
> >
> > I simply don't know about the details of the xhci-mtk internals.
> > It was okay from my tests with mt8173 and I think this will be
> > harmless
> > as this is "better than before".
> >
> > But when I removed get_esit_boundary(), I really have no idea why
> > it was there. I'm wondering if there was another reason of that
> > function
> > other than just preventing out-of-bounds. Maybe chunfeng can answer
> > this?
> We use @esit to prevent out-of-bounds array access. it's not a ring,
> can't insert out-of-bounds value into head slot.

Thanks, so that function was only for out-of-bounds array access.
then I think we just can remove that function and use it as a ring.
Can you tell me _why_ it can't be used as a ring?

I think a transaction (e.g. esit_boundary = 7) can start its first SSPLIT
from Y_7 (offset = 7). But will that allocation be matched with this?

-               if ((offset + sch_ep->num_budget_microframes) > esit_boundary)
-                       break;

I mean I'm not sure why this is needed.

Until now, I couldn't find a way to accept the USB audio headset
with a configuration of { INT-IN 64 + ISOC-OUT 384 + ISOC-IN 192 }
without this patch.

>
> >
> > Thanks!
> >
> > >
> > > thanks,
> > >
> > > greg k-h

WARNING: multiple messages have this Message-ID
From: Ikjoon Jang <ikjn@chromium.org>
To: "Chunfeng Yun (云春峰)" <Chunfeng.Yun@mediatek.com>
Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	 "linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	 "matthias.bgg@gmail.com" <matthias.bgg@gmail.com>,
	 "linux-mediatek@lists.infradead.org"
	<linux-mediatek@lists.infradead.org>,
	 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	 "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	 "mathias.nyman@intel.com" <mathias.nyman@intel.com>
Subject: Re: [RFC PATCH] usb: xhci-mtk: handle bandwidth table rollover
Date: Thu, 12 Aug 2021 17:31:45 +0800	[thread overview]
Message-ID: <CAATdQgD1paUUmWhiLVq-+zq0V6=RTJw89ggk=R6cBUZO+5dB-Q@mail.gmail.com> (raw)
In-Reply-To: <7b48f4c132a8b4b3819282e961fbe8b3ed753069.camel@mediatek.com>

HI,

On Wed, Aug 11, 2021 at 5:02 PM Chunfeng Yun (云春峰)
<Chunfeng.Yun@mediatek.com> wrote:
>
> On Mon, 2021-08-09 at 17:42 +0800, Ikjoon Jang wrote:
> > On Mon, Aug 9, 2021 at 5:11 PM Greg Kroah-Hartman
> > <gregkh@linuxfoundation.org> wrote:
> > >
> > > On Mon, Aug 09, 2021 at 04:59:29PM +0800, Ikjoon Jang wrote:
> > > > xhci-mtk has 64 slots for periodic bandwidth calculations and
> > > > each
> > > > slot represents byte budgets on a microframe. When an endpoint's
> > > > allocation sits on the boundary of the table, byte budgets' slot
> > > > should be rolled over but the current implementation doesn't.
> > > >
> > > > This patch applies a 6 bits mask to the microframe index to
> > > > handle
> > > > its rollover 64 slots and prevent out-of-bounds array access.
> > > >
> > > > Signed-off-by: Ikjoon Jang <ikjn@chromium.org>
> > > > ---
> > > >
> > > >  drivers/usb/host/xhci-mtk-sch.c | 79 +++++++++----------------
> > > > --------
> > > >  drivers/usb/host/xhci-mtk.h     |  1 +
> > > >  2 files changed, 23 insertions(+), 57 deletions(-)
> > >
> > > Why is this "RFC"?  What needs to be addressed in this change
> > > before it
> > > can be accepted?
> >
> > sorry, I had to mention why this is RFC:
> >
> > I simply don't know about the details of the xhci-mtk internals.
> > It was okay from my tests with mt8173 and I think this will be
> > harmless
> > as this is "better than before".
> >
> > But when I removed get_esit_boundary(), I really have no idea why
> > it was there. I'm wondering if there was another reason of that
> > function
> > other than just preventing out-of-bounds. Maybe chunfeng can answer
> > this?
> We use @esit to prevent out-of-bounds array access. it's not a ring,
> can't insert out-of-bounds value into head slot.

Thanks, so that function was only for out-of-bounds array access.
then I think we just can remove that function and use it as a ring.
Can you tell me _why_ it can't be used as a ring?

I think a transaction (e.g. esit_boundary = 7) can start its first SSPLIT
from Y_7 (offset = 7). But will that allocation be matched with this?

-               if ((offset + sch_ep->num_budget_microframes) > esit_boundary)
-                       break;

I mean I'm not sure why this is needed.

Until now, I couldn't find a way to accept the USB audio headset
with a configuration of { INT-IN 64 + ISOC-OUT 384 + ISOC-IN 192 }
without this patch.

>
> >
> > Thanks!
> >
> > >
> > > thanks,
> > >
> > > greg k-h

_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

WARNING: multiple messages have this Message-ID
From: Ikjoon Jang <ikjn@chromium.org>
To: "Chunfeng Yun (云春峰)" <Chunfeng.Yun@mediatek.com>
Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	 "linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	 "matthias.bgg@gmail.com" <matthias.bgg@gmail.com>,
	 "linux-mediatek@lists.infradead.org"
	<linux-mediatek@lists.infradead.org>,
	 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	 "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	 "mathias.nyman@intel.com" <mathias.nyman@intel.com>
Subject: Re: [RFC PATCH] usb: xhci-mtk: handle bandwidth table rollover
Date: Thu, 12 Aug 2021 17:31:45 +0800	[thread overview]
Message-ID: <CAATdQgD1paUUmWhiLVq-+zq0V6=RTJw89ggk=R6cBUZO+5dB-Q@mail.gmail.com> (raw)
In-Reply-To: <7b48f4c132a8b4b3819282e961fbe8b3ed753069.camel@mediatek.com>

HI,

On Wed, Aug 11, 2021 at 5:02 PM Chunfeng Yun (云春峰)
<Chunfeng.Yun@mediatek.com> wrote:
>
> On Mon, 2021-08-09 at 17:42 +0800, Ikjoon Jang wrote:
> > On Mon, Aug 9, 2021 at 5:11 PM Greg Kroah-Hartman
> > <gregkh@linuxfoundation.org> wrote:
> > >
> > > On Mon, Aug 09, 2021 at 04:59:29PM +0800, Ikjoon Jang wrote:
> > > > xhci-mtk has 64 slots for periodic bandwidth calculations and
> > > > each
> > > > slot represents byte budgets on a microframe. When an endpoint's
> > > > allocation sits on the boundary of the table, byte budgets' slot
> > > > should be rolled over but the current implementation doesn't.
> > > >
> > > > This patch applies a 6 bits mask to the microframe index to
> > > > handle
> > > > its rollover 64 slots and prevent out-of-bounds array access.
> > > >
> > > > Signed-off-by: Ikjoon Jang <ikjn@chromium.org>
> > > > ---
> > > >
> > > >  drivers/usb/host/xhci-mtk-sch.c | 79 +++++++++----------------
> > > > --------
> > > >  drivers/usb/host/xhci-mtk.h     |  1 +
> > > >  2 files changed, 23 insertions(+), 57 deletions(-)
> > >
> > > Why is this "RFC"?  What needs to be addressed in this change
> > > before it
> > > can be accepted?
> >
> > sorry, I had to mention why this is RFC:
> >
> > I simply don't know about the details of the xhci-mtk internals.
> > It was okay from my tests with mt8173 and I think this will be
> > harmless
> > as this is "better than before".
> >
> > But when I removed get_esit_boundary(), I really have no idea why
> > it was there. I'm wondering if there was another reason of that
> > function
> > other than just preventing out-of-bounds. Maybe chunfeng can answer
> > this?
> We use @esit to prevent out-of-bounds array access. it's not a ring,
> can't insert out-of-bounds value into head slot.

Thanks, so that function was only for out-of-bounds array access.
then I think we just can remove that function and use it as a ring.
Can you tell me _why_ it can't be used as a ring?

I think a transaction (e.g. esit_boundary = 7) can start its first SSPLIT
from Y_7 (offset = 7). But will that allocation be matched with this?

-               if ((offset + sch_ep->num_budget_microframes) > esit_boundary)
-                       break;

I mean I'm not sure why this is needed.

Until now, I couldn't find a way to accept the USB audio headset
with a configuration of { INT-IN 64 + ISOC-OUT 384 + ISOC-IN 192 }
without this patch.

>
> >
> > Thanks!
> >
> > >
> > > thanks,
> > >
> > > greg k-h

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-08-12  9:31 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-09  8:59 [RFC PATCH] usb: xhci-mtk: handle bandwidth table rollover Ikjoon Jang
2021-08-09  8:59 ` Ikjoon Jang
2021-08-09  8:59 ` Ikjoon Jang
2021-08-09  9:11 ` Greg Kroah-Hartman
2021-08-09  9:11   ` Greg Kroah-Hartman
2021-08-09  9:11   ` Greg Kroah-Hartman
2021-08-09  9:42   ` Ikjoon Jang
2021-08-09  9:42     ` Ikjoon Jang
2021-08-09  9:42     ` Ikjoon Jang
2021-08-11  9:01     ` Chunfeng Yun (云春峰)
2021-08-12  9:31       ` Ikjoon Jang [this message]
2021-08-12  9:31         ` Ikjoon Jang
2021-08-12  9:31         ` Ikjoon Jang
2021-08-12 11:49         ` Chunfeng Yun (云春峰)
2021-08-12 13:47           ` Ikjoon Jang
2021-08-12 13:47             ` Ikjoon Jang
2021-08-12 13:47             ` Ikjoon Jang
2021-08-18  2:43           ` Ikjoon Jang
2021-08-18  2:43             ` Ikjoon Jang
2021-08-18  2:43             ` Ikjoon Jang
2021-08-20  3:37             ` Chunfeng Yun (云春峰)

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='CAATdQgD1paUUmWhiLVq-+zq0V6=RTJw89ggk=R6cBUZO+5dB-Q@mail.gmail.com' \
    --to=ikjn@chromium.org \
    --cc=Chunfeng.Yun@mediatek.com \
    --cc=gregkh@linuxfoundation.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 \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.