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Thu, 01 Oct 2026 07:07:31 -0700 (PDT) Received: from pathway.suse.cz ([176.114.240.130]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a023798b54sm39456895e9.13.2026.10.01.07.07.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Oct 2026 07:07:31 -0700 (PDT) From: Petr Mladek To: John Ogness Cc: Sergey Senozhatsky , Steven Rostedt , Marcos Paulo de Souza , Samuel Thibault , Greg Kroah-Hartman , Jiri Slaby , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Hugo Villeneuve , Fushuai Wang , Kees Cook , Stepan Ionichev , linux-serial@vger.kernel.org, Manuel Lauss , linux-kernel@vger.kernel.org, Petr Mladek Subject: [PATCH v4 0/1] braille: nbcon: Fix Braille console for NBCON API Date: Thu, 1 Oct 2026 16:07:26 +0200 Message-ID: <20261001140727.124398-1-pmladek@suse.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi, this is v4 patch which tries to fix Braille console driver to work with serial console drivers ported to NBCON API. I did a quick turnaround because it would be nice to get it into 7.3. Many people attend Plumbers conference the following week... Changes against v3: + Removed unnecessary "locked" variable. [John] + Allow to use console driver even without write_atomic, except for panic mode [John] + Added parenthesis around (con->flags & CON_BRL) [John] + Exported nbcon_write_context_is_braille() [Sashiko] + Fixed many typos and wording [John] Changes against v2: + Use con->device_lock() for non-panic case. Try even an unsafe acquire in panic(). This simulates the legacy locking using NBCON API. + Return when the nbcon context can't be acquired in panic(). The NBCON API is not ready to ignore the lock. Well, it should never happen in practice because the unsafe acquire... + Avoid the newline prepend logic in all serial consoles ported to NBCON API which have it. Add two APIs for checking whether either "con" or "wctxt" is in Braille mode. + Update commit message and comments in the code. Changes against v1: + Merged into one patch. It is hard to explain nbcon_braille*() API without the user. + Reworked the locking, see the commit message for more details. + Fixed the check of CON_NBCON_ATOMIC_UNSAFE [Sashiko] IMPORTANT: The solution is not safe in PREEMPT_RT. But it is better then nothing. We could either solve it in v3. Or we could fix it later. [v1] https://lore.kernel.org/r/20260922072558.98854-1-pmladek@suse.com [v2] https://lore.kernel.org/r/20260925141729.173943-2-pmladek@suse.com [v3] https://lore.kernel.org/r/20261001093946.112999-1-pmladek@suse.com Petr Mladek (1): braille: nbcon: Allow to use a serial console with NBCON API as Braille console .../accessibility/braille/braille_console.c | 60 +++++++++++++- drivers/tty/serial/8250/8250_port.c | 5 +- drivers/tty/serial/amba-pl011.c | 2 +- drivers/tty/serial/imx.c | 2 +- drivers/tty/serial/sifive.c | 2 +- include/linux/console.h | 15 ++++ kernel/printk/nbcon.c | 79 +++++++++++++++++++ 7 files changed, 159 insertions(+), 6 deletions(-) -- 2.55.0