From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Matthias Klein <matthias.klein@optimeas.de>,
wg@grandegger.com, linux-can@vger.kernel.org,
support@karo-electronics.de
Cc: bigeasy@linutronix.de
Subject: Re: [PATCH V2 5/5] net: can: flexcan: fix for wrong TX error count behaviour on i.MX53
Date: Mon, 28 Jul 2014 09:05:56 +0200 [thread overview]
Message-ID: <53D5F654.6050203@pengutronix.de> (raw)
In-Reply-To: <1406529268-20126-5-git-send-email-matthias.klein@optimeas.de>
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On 07/28/2014 08:34 AM, Matthias Klein wrote:
> Once the CAN-bus is open and a packet is sent, the controller switches
> into the PASSIVE state and the TX error count goes to 0x80. When the
> bus is closed and the packet gets acknowledged the controller switches
> to ERROR-WARNING state and the TX error counter is decremented to 0x7f.
> Everything OK so far.
>
> When now the bus is open again and a packet is sent, the controller
> switches into PASSIVE state and sets the TX error count to 0x86.
> When now the bus is closed the TX error is decremented to 0x85, but
> the state does not change to ERROR-WARNING. Now with each successfully
> transfered packet (in PASSIVE state!) the TX error counter is
> decremented, and when the TX error counter reaches 0x7f the controller
> switched back into ERROR-WARNING state.
My original comment still applies, I don't see a problem with sending
CAN frames in error passive mode.
The only thing that violates the specs is IMHO, that the TX error
counter is incremented > 127 when the bus is open, although is does not
reach 255.
> This fix sets the TX error count back to zero when entering the
> ERROR-WARNING state (after the first retransfered packet is acknowledged).
Why do you this? The expected behaviour is that each successfully
transmitted CAN frame decreases the TX error counter. So it will take a
few frames until you reach a TX error counter of 0 when coming from
error passive.
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
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next prev parent reply other threads:[~2014-07-28 7:06 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-28 6:34 [PATCH V2 1/5] net: can: flexcan: provide propper return code in ISR Matthias Klein
2014-07-28 6:34 ` [PATCH V2 2/5] net: can: flexcan: disable error interrupts in non ERR-Active state Matthias Klein
2014-07-28 6:40 ` Varka Bhadram
2014-07-28 6:34 ` [PATCH V2 3/5] net: can: flexcan: handle state passive -> warning transition Matthias Klein
2014-07-28 6:34 ` [PATCH V2 4/5] can: flexcan: fix transition from and to freeze mode in chip_{,un}freeze Matthias Klein
2014-07-28 6:38 ` Marc Kleine-Budde
2014-07-28 6:34 ` [PATCH V2 5/5] net: can: flexcan: fix for wrong TX error count behaviour on i.MX53 Matthias Klein
2014-07-28 6:39 ` Varka Bhadram
2014-07-28 7:05 ` Marc Kleine-Budde [this message]
2014-07-28 7:08 ` Sebastian Andrzej Siewior
2014-07-28 6:36 ` [PATCH V2 1/5] net: can: flexcan: provide propper return code in ISR Varka Bhadram
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