On 16.11.2022 21:52:55, Markus Schneider-Pargmann wrote: > Currently the driver waits to wakeup the queue until the interrupt for > the transmit event is received and acknowledged. If we want to use the > hardware FIFO, this is too late. > > Instead release the queue as soon as the transmit was transferred into > the hardware FIFO. We are then ready for the next transmit to be > transferred. > > Signed-off-by: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx> > --- > drivers/net/can/m_can/m_can.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c > index 2c01e3f7b23f..4adf03111782 100644 > --- a/drivers/net/can/m_can/m_can.c > +++ b/drivers/net/can/m_can/m_can.c > @@ -1097,10 +1097,9 @@ static irqreturn_t m_can_isr(int irq, void *dev_id) > /* New TX FIFO Element arrived */ > if (m_can_echo_tx_event(dev) != 0) > goto out_fail; > - > - if (netif_queue_stopped(dev) && > - !m_can_tx_fifo_full(cdev)) > + if (!cdev->tx_skb && netif_queue_stopped(dev)) > netif_wake_queue(dev); Please don't start the queue if the FIFO is still full. Is this a gamble, that it will take long enough until the work queue runs that the FIFO is not full anymore? > + Nitpick: Please don't introduce an extra newline here. > } > } > > @@ -1705,6 +1704,8 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev) > if (m_can_tx_fifo_full(cdev) || > m_can_next_echo_skb_occupied(dev, putidx)) > netif_stop_queue(dev); > + else if (cdev->is_peripheral && !cdev->tx_skb && netif_queue_stopped(dev)) > + netif_wake_queue(dev); Same question as above, what happens if the FIFO is full? e.g. in case of a slow bus or the first CAN frame in the FIFO has a low prio... > } > > return NETDEV_TX_OK; > -- > 2.38.1 > > Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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