From: Paul Mackerras <paulus@ozlabs.org>
To: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, xinhui.pan@linux.vnet.ibm.com,
benh@kernel.crashing.org, mpe@ellerman.id.au
Subject: Re: [PATCH v4 2/3] powerpc/xmon: drop the nobt option from xmon plus minor fixes
Date: Fri, 31 Mar 2017 11:36:45 +1100 [thread overview]
Message-ID: <20170331003645.GA12861@fergus.ozlabs.ibm.com> (raw)
In-Reply-To: <20170322192751.30531-3-gpiccoli@linux.vnet.ibm.com>
On Wed, Mar 22, 2017 at 04:27:50PM -0300, Guilherme G. Piccoli wrote:
> The xmon parameter nobt was added long time ago, by commit 26c8af5f01df
> ("[POWERPC] print backtrace when entering xmon"). The problem that time
> was that during a crash in a machine with USB keyboard, xmon wouldn't
> respond to commands from the keyboard, so printing the backtrace wouldn't
> be possible.
>
> Idea then was to show automatically the backtrace on xmon crash for the
> first time it's invoked (if it recovers, next time xmon won't show
> backtrace automatically). The nobt parameter was added _only_ to prevent
> this automatic trace show. Seems long time ago USB keyboards didn't work
> that well!
Xmon still can't use a USB keyboard. It's not a question of how well
USB keyboards work, it's that having a non-interrupt-driven USB stack
with (at least) an OHCI host controller driver and a keyboard driver
in xmon is impractical.
Paul.
next prev parent reply other threads:[~2017-03-31 0:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-22 19:27 [PATCH v4 0/3] powerpc/xmon: improvements and fixes Guilherme G. Piccoli
2017-03-22 19:27 ` [PATCH v4 1/3] powerpc/xmon: Fix an unexpected xmon on/off state change Guilherme G. Piccoli
2017-03-31 12:33 ` [v4, " Michael Ellerman
2017-03-22 19:27 ` [PATCH v4 2/3] powerpc/xmon: drop the nobt option from xmon plus minor fixes Guilherme G. Piccoli
2017-03-31 0:36 ` Paul Mackerras [this message]
2017-03-31 13:06 ` Guilherme G. Piccoli
2017-04-01 10:31 ` Michael Ellerman
2017-03-22 19:27 ` [PATCH v4 3/3] powerpc/xmon: add debugfs entry for xmon Guilherme G. Piccoli
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=20170331003645.GA12861@fergus.ozlabs.ibm.com \
--to=paulus@ozlabs.org \
--cc=benh@kernel.crashing.org \
--cc=gpiccoli@linux.vnet.ibm.com \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
--cc=xinhui.pan@linux.vnet.ibm.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 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).