From: Petr Mladek <pmladek@suse.com>
To: John Ogness <john.ogness@linutronix.de>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
Marcos Paulo de Souza <mpdesouza@suse.com>,
Chris Down <chris@chrisdown.name>,
Naveen Kumar Chaudhary <naveen.osdev@gmail.com>,
linux-kernel@vger.kernel.org, Petr Mladek <pmladek@suse.com>
Subject: [PATCH v5 16/16] printk: Try enable preferred consoles only when there are any
Date: Tue, 29 Sep 2026 14:05:46 +0200 [thread overview]
Message-ID: <20260929120546.328616-17-pmladek@suse.com> (raw)
In-Reply-To: <20260929120546.328616-1-pmladek@suse.com>
try_enable_preferred_console() used to be always called because it
had several hidden effects, namely:
- returned success when a console was pre-enabled using CON_ENABLED
flag.
- enabled Braille consoles which were ignored by "preferred_dev_console"
because they were not associated with /dev/console.
- returned success when a console was enabled by default because
try_enable_default_console() did not return success.
The first two hidden effects were removed in previous patches. The already
fixed handling of pre-enabled consoles actually helps even the 3rd case.
try_enable_default_console() sets CON_ENABLED flag on success and
is later handled as pre-enabled.
Prevent any future hidden effects and call try_enable_preferred_console()
only when some console is preferred.
No behavior change.
Signed-off-by: Petr Mladek <pmladek@suse.com>
---
kernel/printk/printk.c | 26 +++++++++++++++++---------
1 file changed, 17 insertions(+), 9 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 1eb749da9e24..06c49042dd8f 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -4085,7 +4085,7 @@ static int try_enable_default_console(struct console *newcon)
static int try_enable_console(struct console *newcon)
{
- int err;
+ int err = -ENOENT;
/*
* First, try to enable the console driver as a Braille console.
@@ -4124,16 +4124,24 @@ static int try_enable_console(struct console *newcon)
if (err != -ENOENT)
return err;
}
+ } else {
+ /* See if this console matches one we selected on the command line */
+ err = try_enable_preferred_console(newcon, true);
+ if (err != -ENOENT)
+ return err;
+
+ /* If not, try to match against the platform default(s) */
+ err = try_enable_preferred_console(newcon, false);
+ if (err != -ENOENT)
+ return err;
}
- /* See if this console matches one we selected on the command line */
- err = try_enable_preferred_console(newcon, true);
- if (err != -ENOENT)
- return err;
-
- /* If not, try to match against the platform default(s) */
- err = try_enable_preferred_console(newcon, false);
- if (err != -ENOENT)
+ /*
+ * Make sure that pre-enabled consoles won't get registered when
+ * something went wrong. This is just a paranoid check that all
+ * branches above returned on error.
+ */
+ if (WARN_ON(err != -ENOENT))
return err;
/*
--
2.55.0
prev parent reply other threads:[~2026-09-29 12:09 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-29 12:05 [PATCH v5 00/16] printk: Clean up preferred console handling Petr Mladek
2026-09-29 12:05 ` [PATCH v5 01/16] printk: Rename struct console_cmdline to preferred_console Petr Mladek
2026-09-29 12:05 ` [PATCH v5 02/16] printk: Rename preferred_console to preferred_dev_console Petr Mladek
2026-09-29 12:05 ` [PATCH v5 03/16] printk: Cleanup _braille_(un)register_console() wrappers Petr Mladek
2026-09-29 12:05 ` [PATCH v5 04/16] printk: Separate code for adding/updating preferred console metadata Petr Mladek
2026-09-29 12:05 ` [PATCH v5 05/16] printk: Prefer the console either via name or devname exclusively Petr Mladek
2026-09-29 12:05 ` [PATCH v5 06/16] printk: Check that index is not defined when a console is preferred via devname Petr Mladek
2026-09-29 12:05 ` [PATCH v5 07/16] printk: Ensure consistent name and devname when updating preferred console Petr Mladek
2026-09-29 12:05 ` [PATCH v5 08/16] printk: Do not quietly ignore adding entry for a preferred console when there is no space Petr Mladek
2026-09-29 12:05 ` [PATCH v5 09/16] printk: Allow to override options via the command line Petr Mladek
2026-09-29 12:05 ` [PATCH v5 10/16] printk: Allow to debug misuse of add_or_update_preferred_console() Petr Mladek
2026-09-29 12:05 ` [PATCH v5 11/16] console/braille: Lock console->setup() call during the registration Petr Mladek
2026-09-29 12:05 ` [PATCH v5 12/16] printk: Separate code for enabling console Petr Mladek
2026-09-29 12:05 ` [PATCH v5 13/16] printk: Try to register each console as Braille first Petr Mladek
2026-09-29 12:05 ` [PATCH v5 14/16] printk: Do not set Braille console as preferred_console Petr Mladek
2026-09-29 12:05 ` [PATCH v5 15/16] printk: Modify try_enable_default_console() to return error/success Petr Mladek
2026-09-29 12:05 ` Petr Mladek [this message]
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=20260929120546.328616-17-pmladek@suse.com \
--to=pmladek@suse.com \
--cc=chris@chrisdown.name \
--cc=john.ogness@linutronix.de \
--cc=linux-kernel@vger.kernel.org \
--cc=mpdesouza@suse.com \
--cc=naveen.osdev@gmail.com \
--cc=rostedt@goodmis.org \
--cc=senozhatsky@chromium.org \
/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
all inboxes | Powered by JetHome®