On Wed, Sep 10, 2014 at 09:29:57PM +0200, Sebastian Andrzej Siewior wrote: > +/* > + * This two wrapper ensure, that enable_runtime_pm_tx() can be called more than These two wrappers ensure that enable_runtime_pm_tx() ... > + * once and disable_runtime_pm_tx() will still disable RPM because the fifo is > + * empty and the HW can idle again. > + */ > +static void serial8250_rpm_get_tx(struct uart_8250_port *p) > +{ > + unsigned char rpm_active; > + > + if (!(p->capabilities & UART_CAP_RPM)) > + return; > + > + rpm_active = xchg(&p->rpm_tx_active, 1); > + if (rpm_active) > + return; > + pm_runtime_get_sync(p->port.dev); > +} > + > +static void serial8250_rpm_put_tx(struct uart_8250_port *p) > +{ > + unsigned char rpm_active; > + > + if (!(p->capabilities & UART_CAP_RPM)) > + return; > + > + rpm_active = xchg(&p->rpm_tx_active, 0); > + if (!rpm_active) > + return; > + pm_runtime_mark_last_busy(p->port.dev); > + pm_runtime_put_autosuspend(p->port.dev); > +} > + > @@ -1469,7 +1531,12 @@ void serial8250_tx_chars(struct uart_8250_port *up) > > DEBUG_INTR("THRE..."); > > - if (uart_circ_empty(xmit)) > + /* > + * With RPM enabled, we have to wait once the FIFO is empty before the s,once,until,? Or do I not understand the sentence correctly? > + * HW can go idle. So we get here once again with empty FIFO and disable > + * the interrupt and RPM in __stop_tx() > + */ > + if (uart_circ_empty(xmit) && !(up->capabilities & UART_CAP_RPM)) > __stop_tx(up); > } > EXPORT_SYMBOL_GPL(serial8250_tx_chars); -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html