Re: [PATCH v5 1/2] can: kvaser_usb: Comply with firmware max tx URBs value

From: Ahmed S. Darwish
Date: Mon Mar 16 2015 - 08:16:48 EST


On Sun, Mar 15, 2015 at 07:08:23PM +0100, Marc Kleine-Budde wrote:
> On 03/15/2015 04:03 PM, Ahmed S. Darwish wrote:
> > From: Ahmed S. Darwish <ahmed.darwish@xxxxxxxxx>
> >
> > Current driver code arbitrarily assumes a max outstanding tx
> > value of 16 parallel transmissions. Meanwhile, the device
> > firmware provides its actual maximum inside its reply to the
> > CMD_GET_SOFTWARE_INFO message.
> >
> > Under heavy tx traffic, if the interleaved transmissions count
> > increases above the limit reported by firmware, the firmware
> > breaks up badly, reports a massive list of internal errors, and
> > the candump traces hardly matches the actual frames sent and
> > received.
> >
> > On the other hand, in certain models, the firmware can support
> > up to 48 tx URBs instead of just 16, increasing the driver
> > throughput by two-fold and reducing the possibility of -ENOBUFs.
> >
> > Thus dynamically set the driver's max tx URBs value according
> > to firmware replies.
> >
> > Signed-off-by: Ahmed S. Darwish <ahmed.darwish@xxxxxxxxx>
>
> > @@ -1928,7 +1940,7 @@ static int kvaser_usb_init_one(struct usb_interface *intf,
> > return err;
> > }
> >
> > - netdev_dbg(netdev, "device registered\n");
> > + netdev_info(netdev, "device registered\n");
>
> This makes the driver more noisy, I'd like to drop that hunk, okay? No
> need to resend.
>

Sure, go ahead.

I have my reasons for that hunk above, but we can always discuss
this in another separate patch ;-)

Thanks,
Darwish
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