Return-Path: MIME-Version: 1.0 In-Reply-To: <47E39EED-4F96-4128-BAD1-09CDE4FC7A2E@holtmann.org> References: <20170901080744.11544-1-andrzej.kaczmarek@codecoup.pl> <47E39EED-4F96-4128-BAD1-09CDE4FC7A2E@holtmann.org> From: Andrzej Kaczmarek Date: Fri, 1 Sep 2017 15:26:15 +0200 Message-ID: Subject: Re: [PATCH 1/2] doc/btsnoop: Add nop opcode To: Marcel Holtmann Cc: linux-bluetooth@vger.kernel.org Content-Type: multipart/alternative; boundary="94eb2c05c5d2ccea7b055820b59f" List-ID: --94eb2c05c5d2ccea7b055820b59f Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Marcel, On Fri, Sep 1, 2017 at 2:29 PM, Marcel Holtmann wrote= : > Hi Andrzej, > > > This adds 'no operation' opcode for the cases where we do not want to > > include any particular payload, just the header is valid. > > > > For example, when some packets are dropped over TTY implementation can > > pass this information only in some other packet and this won't happen > > until there's actually something to send. With this addition it can > > just send nop after some time to indicate there were packets dropped. > > --- > > doc/btsnoop.txt | 7 +++++++ > > 1 file changed, 7 insertions(+) > > > > diff --git a/doc/btsnoop.txt b/doc/btsnoop.txt > > index 975a53f6d..865b81554 100644 > > --- a/doc/btsnoop.txt > > +++ b/doc/btsnoop.txt > > @@ -115,6 +115,13 @@ User Logging > > > > User logging information. > > > > +NOP > > +----------- > > + > > + Code: 0xffff > > + > > + No operation. > > + > > Hmmm. I am not a huge fan of this. Then I see that we defined the ext_hdr > that allows to deal with the dropped packets. > > I need to think about this a bit since there are some other opcode > extensions we have to do for certain cases where we have unexpected > packets. Right now I would propose to use vendor diagnostic or system not= e > with empty payload. > Vendor diagnostic would produce a message in btmon which may be misleading and system note with empty payload will print some garbage (i.e. previous contents=E2=80=8B of buffer) since message is not null-terminated. But in this case I can just fix btmon to skip system notes with no payload and it will be basically the same as nop - does it sound good enough for now? > > Regards > > Marce > =E2=80=8Bl > Best regards, Andrzej=E2=80=8B > --94eb2c05c5d2ccea7b055820b59f Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

Hi Marcel,

On Fri, Sep 1, 2017 at 2:29 PM, Marcel Holtmann <= marcel@holtmann.org> wrote:

Hi Andrzej,

> This adds 'no operation' opcode for the cases where we do not = want to
> include any particular payload, just the header is valid.
>
> For example, when some packets are dropped over TTY implementation can=
> pass this information only in some other packet and this won't hap= pen
> until there's actually something to send. With this addition it ca= n
> just send nop after some time to indicate there were packets dropped.<= br> > ---
> doc/btsnoop.txt | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/doc/btsnoop.txt b/doc/btsnoop.txt
> index 975a53f6d..865b81554 100644
> --- a/doc/btsnoop.txt
> +++ b/doc/btsnoop.txt
> @@ -115,6 +115,13 @@ User Logging
>
>=C2=A0 =C2=A0 =C2=A0 =C2=A0User logging information.
>
> +NOP
> +-----------
> +
> +=C2=A0 =C2=A0 =C2=A0Code:=C2=A0 =C2=A0 =C2=A0 =C2=A0 0xffff
> +
> +=C2=A0 =C2=A0 =C2=A0No operation.
> +

Hmmm. I am not a huge fan of this. Then I see that we defined the ex= t_hdr that allows to deal with the dropped packets.

I need to think about this a bit since there are some other opcode extensio= ns we have to do for certain cases where we have unexpected packets. Right = now I would propose to use vendor diagnostic or system note with empty payl= oad.

Vendor diagnostic would produce= a message in btmon which may be misleading and system note with empty payl= oad will print some garbage (i.e. previous contents=E2=80=8B of buffer) sin= ce message is not null-terminated.

But in this case I can just = fix btmon to skip system notes with no payload and it will be basically the= same as nop - does it sound good enough for now?

=C2= =A0

Regards

Marce
=E2=80=8Bl

Best regards,<= /font>

Andrzej=E2=80=8B

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