Re: [PATCH tty v11 1/2] serial: 8250: Switch to nbcon console, take 2
John Ogness <[email protected]>
| Newsgroups | org.kernel.vger.linux-tegra,org.kernel.vger.linux-kernel,org.kernel.vger.linux-serial |
|---|---|
| Message-ID | <[email protected]> |
On 2026-08-21, Jon Hunter <[email protected]> wrote: > I replaced the WARN with a pr_err() and I see the same issue. Thanks for testing. But just to be certain, can you restore the original code (with the warning) and apply this horrible hack to force atomic printing? I want to be certain that the problem goes away when nbcon deferred printing is not active. For thet test you should boot normally (without keep_bootcon). ===== BEGIN HACK ===== diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h index 85fbf1801cbe0..5806815fa11b2 100644 --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h @@ -202,6 +202,7 @@ static inline void printk_get_console_flush_type(struct console_flush_type *ft) ft->nbcon_offload = true; else ft->nbcon_atomic = true; + ft->nbcon_atomic = true; } /* Legacy consoles are flushed directly when possible. */ diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c index 4b03b019cd5ee..152d9ac28176d 100644 --- a/kernel/printk/nbcon.c +++ b/kernel/printk/nbcon.c @@ -1185,6 +1185,7 @@ static bool nbcon_kthread_should_wakeup(struct console *con, struct nbcon_contex if (kthread_should_stop()) return true; + return false; /* * Block the kthread when the system is in an emergency or panic mode. ===== END HACK ===== I am expecting that this will work and the warning will be cleanly visible on the UART console. If the above test was successful, I am wondering if cpuidle should be disabling the deferred printing as this seems quite similar to suspend. Could you perform another test using the following hack _instead_ of the above hack? This is probably a bit extreme since it does more than just disable deferring, but it could help us figure out what is going on. ===== BEGIN HACK2 ===== diff --git a/drivers/cpuidle/cpuidle-tegra.c b/drivers/cpuidle/cpuidle-tegra.c index aca907a62bb5d..0fb449e23f677 100644 --- a/drivers/cpuidle/cpuidle-tegra.c +++ b/drivers/cpuidle/cpuidle-tegra.c @@ -15,6 +15,7 @@ #define pr_fmt(fmt) "tegra-cpuidle: " fmt #include <linux/atomic.h> +#include <linux/console.h> #include <linux/cpuidle.h> #include <linux/cpumask.h> #include <linux/cpu_pm.h> @@ -165,6 +166,8 @@ static __cpuidle int tegra_cpuidle_state_enter(struct cpuidle_device *dev, { int err; + console_suspend_all(); + /* * CC6 state is the "CPU cluster power-off" state. In order to * enter this state, at first the secondary CPU cores need to be @@ -176,7 +179,7 @@ static __cpuidle int tegra_cpuidle_state_enter(struct cpuidle_device *dev, if (index == TEGRA_CC6) { err = tegra_cpuidle_coupled_barrier(dev); if (err) - return err; + goto out; } local_fiq_disable(); @@ -204,6 +207,8 @@ static __cpuidle int tegra_cpuidle_state_enter(struct cpuidle_device *dev, cpu_pm_exit(); tegra_pm_clear_cpu_in_lp2(); local_fiq_enable(); +out: + console_resume_all(); return err ?: index; } diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 3fcdf4b4e2e53..8d126b5068684 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2787,7 +2787,7 @@ void console_suspend_all(void) struct console *con; if (console_suspend_enabled) - pr_info("Suspending console(s) (use no_console_suspend to debug)\n"); + pr_info_once("Suspending console(s) (use no_console_suspend to debug)\n"); /* * Flush any console backlog and then avoid queueing irq_work until ===== END HACK2 ===== John Ogness