11 Nov
2021
11 Nov
'21
8:28 a.m.
On 2021-11-10, Sultan Alsawaf sultan@kerneltoast.com wrote:
On Wed, Nov 10, 2021 at 11:13:37AM +0106, John Ogness wrote:
Even after we introduce kthread printers, there will still be situations where direct printing is used: booting (before kthreads exist) and shutdown/suspend/crash situations, when the kthreads may not be active.
Although I'm unaware of any ongoing kthread printer work, I'm curious to know how a kthread approach wouldn't employ a try_to_wake_up() from directly inside printk(), since the try_to_wake_up() hit from inside the fbcon code is what caused my deadlock.
The kthread approach triggers irq_work from printk(). The kthread printer is then woken from the irq_work.
John Ogness