public inbox for u-boot@lists.denx.de
 help / color / mirror / Atom feed
From: Wolfgang Denk <wd@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 00/13] log: Add a new logging feature
Date: Wed, 20 Sep 2017 21:55:48 +0200	[thread overview]
Message-ID: <20170920195548.3FE3B120302@gemini.denx.de> (raw)
In-Reply-To: <20170916212331.170463-1-sjg@chromium.org>

Dear Simon,

sorry for jumping in so late...

In message <20170916212331.170463-1-sjg@chromium.org> you wrote:
>
> At present U-Boot has a logbuffer feature which records output in a memory
> buffer for later display or storage. This is useful but is not at present
> enabled for any board.

Background explanation:  When this was implemented, the buffer
handling was fully compatible with the Linux kernel logbuffer.
And U-Boot was able to reserve memory (at the top of the RAM) that
could be shared between U-Boot and Linux, so you could for example 
write U-Boot POST results into the log buffer, and read it using
standard syslog tools in Linux.  Or keep the panic messages of the
previous crash and read it after reboot.

IIRC this was in production use only on Power architectre systems,
and it broke (and nover got fixed) when the Linux log buffer was
reworked.

> This series introduced a new logging system which supports:
> - various log levels from panic to debug
> - log categories including all uclasses and a few others
> - log drivers to which all log records can be sent
> - log filters which control which log records make it to which drivers

You don't mention it here, but would it be possible to keep
compatibility with the Linux logbuffer implementation in mind?

So we could re-implement this shared logbuffer thingy in case
someone finds it useful?

Thanks!

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
The only thing necessary for the triumph of evil is for good  men  to
do nothing.                                            - Edmund Burke

  parent reply	other threads:[~2017-09-20 19:55 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-16 21:23 [U-Boot] [PATCH 00/13] log: Add a new logging feature Simon Glass
2017-09-16 21:23 ` [U-Boot] [PATCH 01/13] Revert "sandbox: remove os_putc() and os_puts()" Simon Glass
2017-09-17 12:48   ` Bin Meng
2017-09-17 17:55     ` Simon Glass
2017-09-16 21:23 ` [U-Boot] [PATCH 02/13] Revert "sandbox: Drop special case console code for sandbox" Simon Glass
2017-09-17 12:50   ` Bin Meng
2017-09-17 17:55     ` Simon Glass
2017-09-16 21:23 ` [U-Boot] [PATCH 03/13] Move debug and logging support to a separate header Simon Glass
2017-09-17 12:52   ` Bin Meng
2017-09-16 21:23 ` [U-Boot] [PATCH 04/13] mtdparts: Correct use of debug() Simon Glass
2017-09-17 12:54   ` Bin Meng
2017-09-16 21:23 ` [U-Boot] [PATCH 05/13] Drop the log buffer Simon Glass
2017-09-17 12:58   ` Bin Meng
2017-09-16 21:23 ` [U-Boot] [PATCH 06/13] log: Add an implemention of logging Simon Glass
2017-09-18  3:45   ` Bin Meng
2017-09-20 13:50     ` Simon Glass
2017-09-20 14:41       ` Bin Meng
2017-09-20 14:51         ` Dr. Philipp Tomsich
2017-09-21  4:58         ` Simon Glass
2017-09-22 13:37           ` Bin Meng
2017-09-25  2:14             ` Simon Glass
2017-09-20  2:51   ` Masahiro Yamada
2017-09-20 13:49     ` Simon Glass
2017-09-20 14:37       ` Dr. Philipp Tomsich
2017-09-20 17:34         ` Masahiro Yamada
2017-09-20 17:51           ` Dr. Philipp Tomsich
2017-09-27 16:19             ` Masahiro Yamada
2017-09-20 17:19       ` Masahiro Yamada
2017-09-26 19:10         ` Simon Glass
2017-09-27 17:11           ` Masahiro Yamada
2017-09-28 12:39             ` Simon Glass
2017-09-16 21:23 ` [U-Boot] [PATCH 07/13] log: Add a console driver Simon Glass
2017-09-18  3:45   ` Bin Meng
2017-09-26 19:10     ` Simon Glass
2017-09-16 21:23 ` [U-Boot] [PATCH 08/13] log: Add a 'log level' command Simon Glass
2017-09-18  3:46   ` Bin Meng
2017-09-16 21:23 ` [U-Boot] [PATCH 09/13] log: Add a test command Simon Glass
2017-09-18  3:47   ` Bin Meng
2017-09-16 21:23 ` [U-Boot] [PATCH 10/13] log: Plumb logging into the init sequence Simon Glass
2017-09-18  3:47   ` Bin Meng
2017-09-16 21:23 ` [U-Boot] [PATCH 11/13] log: sandbox: Enable logging Simon Glass
2017-09-18  3:47   ` Bin Meng
2017-09-16 21:23 ` [U-Boot] [PATCH 12/13] log: test: Add a pytest for logging Simon Glass
2017-09-16 21:23 ` [U-Boot] [PATCH 13/13] log: Add documentation Simon Glass
2017-09-18  3:47   ` Bin Meng
2017-09-20  3:04   ` Masahiro Yamada
2017-09-20 13:49     ` Simon Glass
2017-09-20  2:32 ` [U-Boot] [PATCH 00/13] log: Add a new logging feature Masahiro Yamada
2017-09-20 20:20   ` Heinrich Schuchardt
2017-09-21  4:58     ` Simon Glass
2017-09-20 19:55 ` Wolfgang Denk [this message]
2017-09-21  4:58   ` Simon Glass

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=20170920195548.3FE3B120302@gemini.denx.de \
    --to=wd@denx.de \
    --cc=u-boot@lists.denx.de \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox