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From:   jim.cromie@gmail.com
Date:   Fri, 3 Nov 2023 21:05:55 -0600
Message-ID: <CAJfuBxxVGaqG4wVu-kM3ynA8ARTD6DFPBuz0a1GqunMqdvRBgQ@mail.gmail.com>
Subject: Re: [PATCH v1 10/12] dyndbg: add processing of T(race) flag argument
To:     =?UTF-8?Q?=C5=81ukasz_Bartosik?= <lb@semihalf.com>
Cc:     Jason Baron <jbaron@akamai.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
        Douglas Anderson <dianders@chromium.org>,
        Guenter Roeck <groeck@google.com>,
        Yaniv Tzoreff <yanivt@google.com>,
        Benson Leung <bleung@google.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Vincent Whitchurch <vincent.whitchurch@axis.com>,
        Pekka Paalanen <ppaalanen@gmail.com>,
        Sean Paul <seanpaul@chromium.org>,
        Daniel Vetter <daniel@ffwll.ch>, linux-kernel@vger.kernel.org,
        upstream@semihalf.com
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On Fri, Nov 3, 2023 at 7:10=E2=80=AFAM =C5=81ukasz Bartosik <lb@semihalf.co=
m> wrote:
>
> Add processing of argument provided to T(race) flag.
> The argument value determines destination of debug logs:
>
> 0 - debug logs will be written to prdbg and devdbg trace events
> [1..255] - debug logs will be written to trace instance
>
> A user can provide trace destination by folowing T flag with
> ":" and trace destination value in range [0..255], for example:
>
> echo "module thunderbolt =3DpT:7" > /sys/kernel/debug/dynamic_debug/contr=
ol
> echo "module thunderbolt =3DlT:7,p" > /sys/kernel/debug/dynamic_debug/con=
trol
>
> When T flag with argument is followed by other flags then the next flag h=
as
> to be preceded with ",".
>

the trailing , seems punctuation heavy.
Could we just stipulate that any :string  (leading : trailing anything)
be the last flag in the spec ?
bare T flags are not constrained otherwise.
seems fine as API-spec-by-error-codes.


> When no value is provided trace destination defaults to 0, for example:
>
> echo "module thunderbolt =3DT" > /sys/kernel/debug/dynamic_debug/control
> echo "module thunderbolt =3DlTp" > /sys/kernel/debug/dynamic_debug/contro=
l

no colon after T means p is a flag, not a destination name