From: Marcos Paulo de Souza <mpdesouza@suse.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
John Ogness <john.ogness@linutronix.de>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jirislaby@kernel.org>,
Jason Wessel <jason.wessel@windriver.com>,
Daniel Thompson <danielt@kernel.org>,
Douglas Anderson <dianders@chromium.org>,
Richard Weinberger <richard@nod.at>,
Anton Ivanov <anton.ivanov@cambridgegreys.com>,
Johannes Berg <johannes@sipsolutions.net>,
linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
kgdb-bugreport@lists.sourceforge.net,
linux-um@lists.infradead.org
Subject: Re: [PATCH 1/7] printk: Make console_{suspend,resume} handle CON_SUSPENDED
Date: Mon, 23 Jun 2025 15:45:37 -0300 [thread overview]
Message-ID: <49eed036f3c230d066ff44620c222fe5a2c3da1a.camel@suse.com> (raw)
In-Reply-To: <aEq9_kOoLSQwuYBq@pathway.suse.cz>
On Thu, 2025-06-12 at 13:46 +0200, Petr Mladek wrote:
> On Fri 2025-06-06 23:53:43, Marcos Paulo de Souza wrote:
> > Since commit 9e70a5e109a4 ("printk: Add per-console suspended
> > state") the
> > CON_SUSPENDED flag was introced, and this flag was being checked on
> > console_is_usable function, which returns false if the console is
> > suspended.
> >
> > No functional changes.
>
> I double checked potential functional changes. In particular, I
> checked where the CON_ENABLED and CON_SUSPENDED flags were used.
>
> Both flags seems to have the same effect in most situations,
> for example, in console_is_usable() or console_unblank().
>
> But there seems to be two exceptions: kdb_msg_write() and
> show_cons_active(). These two functions check only
> the CON_ENABLED flag. And they think that the console is
> usable when the flag is set.
>
> The change in this patch would change the behavior of the two
> functions during suspend. It is later fixed by the 3rd and 4th
> patch. But it might cause regressions during bisections.
>
> It is probably not a big deal because the system is not much
> usable during the suspend anyway. But still, I would feel more
> comfortable if we prevented the "temporary" regression.
>
> I see two possibilities:
>
> 1. Merge the 3rd and 4th patch into this one. It would change
> the semantic in a single patch.
I liked the suggestion, I'll do it in the next revision. Thanks for
looking into it!
>
> 2. First update kdb_msg_write() and show_cons_active()
> to check both CON_ENABLE and CON_SUSPENDED flags.
>
> The 1st solution probably makes more sense because we are going
> to remove the CON_ENABLE flag in the end. And even the merged
> patch is small enough.
>
> Best Regards,
> Petr
next prev parent reply other threads:[~2025-06-24 0:32 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-07 2:53 [PATCH 0/7] printk cleanup - part 2 Marcos Paulo de Souza
2025-06-07 2:53 ` [PATCH 1/7] printk: Make console_{suspend,resume} handle CON_SUSPENDED Marcos Paulo de Souza
2025-06-12 11:46 ` Petr Mladek
2025-06-23 18:45 ` Marcos Paulo de Souza [this message]
2025-06-07 2:53 ` [PATCH 2/7] printk: Use consoles_suspended flag when suspending/resuming all consoles Marcos Paulo de Souza
2025-06-13 15:20 ` Petr Mladek
2025-06-20 14:43 ` John Ogness
2025-06-24 8:40 ` Petr Mladek
2025-06-24 11:04 ` John Ogness
2025-06-25 8:48 ` Petr Mladek
2025-06-23 18:53 ` Marcos Paulo de Souza
2025-06-07 2:53 ` [PATCH 3/7] drivers: tty: Check CON_SUSPENDED instead of CON_ENABLED Marcos Paulo de Souza
2025-06-12 11:48 ` Petr Mladek
2025-06-07 2:53 ` [PATCH 4/7] drivers: serial: kgdboc: " Marcos Paulo de Souza
2025-06-09 20:13 ` Doug Anderson
2025-06-10 20:03 ` Marcos Paulo de Souza
2025-06-10 23:18 ` Doug Anderson
2025-06-12 13:57 ` Petr Mladek
2025-06-12 23:16 ` Doug Anderson
2025-06-13 10:52 ` Petr Mladek
2025-06-13 16:44 ` Doug Anderson
2025-06-07 2:53 ` [PATCH 5/7] arch: um: kmsg_dump: Don't check for CON_ENABLED Marcos Paulo de Souza
2025-06-16 13:33 ` Petr Mladek
2025-06-20 15:45 ` John Ogness
2025-06-07 2:53 ` [PATCH 6/7] debug: kgd_io: " Marcos Paulo de Souza
2025-06-16 13:56 ` Petr Mladek
2025-06-30 0:31 ` Marcos Paulo de Souza
2025-06-07 2:53 ` [PATCH 7/7] printk: Don't check for CON_ENABLED on console_unblank Marcos Paulo de Souza
2025-06-16 14:02 ` Petr Mladek
2025-06-17 9:32 ` Geert Uytterhoeven
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