On 2024-08-01, Jocelyn Falempe <jfalempe@xxxxxxxxxx> wrote: > * It uses a circular buffer so the console->write() callback is very > quick, and will never stall. > * Drawing is done asynchronously using a workqueue. For CON_NBCON, neither of the above points are necessary. You can draw directly from the write_thread() callback. See below: > +static bool drm_log_work_draw(void) > +{ > + unsigned int len; > + char buf[512]; > + > + len = drm_log_buf_read(buf, sizeof(buf)); > + if (len) > + drm_log_draw_all(buf, len); > + return len != 0; > +} For CON_NBCON, this is essentially your write_thread() callback: void drm_log_write_thread(struct console *con, struct nbcon_write_context *wctxt) { drm_log_draw_all(wctxt->outbuf, wctxt->len); } You cannot implement a write_atomic() callback because the console must be able to print directly in NMI context and must not defer. But write_atomic() is optional, so you should be fine there. Disclaimer: Only in PREEMPT_RT patchset at the moment. John Ogness