Re: [PATCH V5 1/1] can: Add support for esd CAN PCIe/402 card

From: "Ahmed S. Darwish" <darwish.07@gmail.com>
To: "Thomas Körper" <Thomas.Koerper@esd.eu>
Cc: Andri Yngvason <andri.yngvason@marel.com>,
	Marc Kleine-Budde <mkl@pengutronix.de>,
	"linux-can@vger.kernel.org" <linux-can@vger.kernel.org>
Subject: Re: [PATCH V5 1/1] can: Add support for esd CAN PCIe/402 card
Date: Tue, 17 Mar 2015 09:26:39 +0200	[thread overview]
Message-ID: <20150317072639.GA2802@Darwish.PC> (raw)
In-Reply-To: <8CE1D0B9BFD2404DA079DDE1814A6F2E03294EFD39B3@esd-s3.esd.local>

Hi Thomas,

On Tue, Mar 17, 2015 at 07:30:02AM +0100, Thomas Körper wrote:
> Hi Andri,
> 
> I've looked at the sources you mentioned, but I'm a little bit unsure now /
> the handling seems not perfectly consistent to me. (flexcan calls
> can_change_state() with tx/rx_state of 0 in the bus off path.
>

There're discrpeancies indeed on the BUSOFF path:

1) flexcan calls can_change_state(dev, cf, 0, 0). kvaser and others
   do can_change_state(dev, cf, tx, rx) where either tx or rx =
   CAN_STATE_BUS_OFF. In this case, kvaser and the other drivers
   are the _correct_ behavior. This is validated by can-dev
   can_chage_state() code:

	if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
		cf->can_id |= CAN_ERR_BUSOFF;
		return;
	}

2) flexcan calls can_bus_off(dev), while kvaser goes a layer deeper
   and directly calls netif_carrier_off(netdev). In this case,
   flexcan is the more correct behavior.

Thanks,
Darwish