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Miller" , Andrea Righi , Andrew Morton , Arnd Bergmann , Ben Segall , Breno Leitao , Changwoo Min , David Vernet , Dietmar Eggemann , Eric Dumazet , Ingo Molnar , Jakub Kicinski , John Ogness , Juri Lelli , Paolo Abeni , Peter Zijlstra , Sergey Senozhatsky , Simon Horman , Steven Rostedt , Tejun Heo , Vincent Guittot , Vlad Poenaru Subject: Re: [PATCH 1/2] bug: Provide WARN_ON.*DEFERRED() macros for console deferred output Message-ID: References: <20260623142650.265721-1-bigeasy@linutronix.de> <20260623142650.265721-2-bigeasy@linutronix.de> <038a11a7-4ced-49ae-b605-2058733e841a@amd.com> <20260624062642.5DER6vrP@linutronix.de> <20260624152431.Ufq0jT8r@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260624152431.Ufq0jT8r@linutronix.de> On Wed 2026-06-24 17:24:31, Sebastian Andrzej Siewior wrote: > On 2026-06-24 11:17:31 [+0200], Petr Mladek wrote: > > For Linus, it was a no-go, definitely. > … > > I would vote for adding the WARN_*DEFERRED() into the scheduler code > > at least until majority of console drivers are converted to nbcon API. > > I see four nbcon serial console drivers (+netconsole, + drm_log). We > have at least four times that many console drivers. What is the > majority from your point of view? The 8250 should cover all of x86. Good question. IMHO, there are about 100 console drivers: $> git grep "struct console.*= {" | wc -l 107 But I guess that many of them are some old rarely used ones. I tried to google amount of market share from various architectures and it seems that most spread are: arm, x86_64, and risc-v. Arm might already be mostly covered by pl011. x86_64 will be covered by 8250. I am not sure about risc-v. It seems that it might use 8250 as well at least in virtual machines. Also there is drivers/tty/hvc/hvc_riscv_sbi.c. Hmm, 8250 might the breakpoint. Maybe, we could leave the rest as a motivation to convert the console driver instead of adding workarounds using the printk_deferred() mechanism. That said, AFAIK, the netconsole is often used when the device does not have a serial console. And it is pity that it does not have the .write_atomic callbacks implemented. Best Regards, Petr