From: Alexander Stein <alexander.stein@systec-electronic.com>
To: David Jander <david@protonic.nl>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>,
Wolfgang Grandegger <wg@grandegger.com>,
linux-can@vger.kernel.org
Subject: Re: [PATCH v5] can: flexcan: Re-write receive path to use MB queue instead of FIFO
Date: Mon, 29 Sep 2014 15:29:28 +0200 [thread overview]
Message-ID: <8124948.gcTnPkg5PL@ws-stein> (raw)
In-Reply-To: <1411995175-13540-1-git-send-email-david@protonic.nl>
On Monday 29 September 2014 14:52:55, David Jander wrote:
> The FlexCAN controller has a RX FIFO that is only 6 messages deep, and a
> mailbox space capable of holding up to 63 messages.
>
> This space was largely unused, limiting the permissible latency from interrupt
> to NAPI to only 6 messages. This patch uses all available MBs for message
> reception and frees the MBs in the IRQ handler to greatly decrease the
> likelihood of receive overruns.
>
> Signed-off-by: David Jander <david@protonic.nl>
AFAICT, If you disable Rx FIFO mode, you essentially break RTR reception on (at least) i.MX3. Please refere to the reference manual 24.4.8.1 Remote Frames.
Vybrid and i.MX6 (not sure about i.MX5) seem to have more features about RTR reception.
Best regards,
Alexander
next prev parent reply other threads:[~2014-09-29 13:37 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-29 12:52 [PATCH v5] can: flexcan: Re-write receive path to use MB queue instead of FIFO David Jander
2014-09-29 13:29 ` Alexander Stein [this message]
2014-09-29 14:39 ` David Jander
2014-09-29 15:02 ` Alexander Stein
2014-09-30 7:13 ` David Jander
2014-09-30 7:43 ` Alexander Stein
2014-10-01 6:29 ` David Jander
2014-10-01 7:11 ` Alexander Stein
2014-10-01 7:15 ` Marc Kleine-Budde
2014-10-01 8:29 ` Alexander Stein
2014-10-01 9:07 ` David Jander
2014-10-01 9:19 ` Alexander Stein
2014-10-01 9:34 ` David Jander
2014-10-01 9:58 ` Marc Kleine-Budde
2014-10-06 7:28 ` David Jander
2014-10-06 10:00 ` Marc Kleine-Budde
2014-10-06 11:17 ` David Jander
2014-10-07 9:30 ` [RFC PATCH 1/2] can: rx-fifo: Increase MB size limit from 32 to 64 David Jander
2014-10-07 9:30 ` [RFC PATCH 2/2] can: rx-fifo: Add support for IRQ readout and NAPI poll David Jander
2014-10-07 13:17 ` [RFC PATCH 1/2] can: rx-fifo: Increase MB size limit from 32 to 64 Marc Kleine-Budde
2014-10-07 13:27 ` David Jander
2014-10-07 14:18 ` Marc Kleine-Budde
2014-10-08 9:08 ` [PATCH v5] can: flexcan: Re-write receive path to use MB queue instead of FIFO David Jander
2014-10-08 9:56 ` Marc Kleine-Budde
2014-10-08 10:36 ` Alexander Stein
2014-10-08 10:43 ` Marc Kleine-Budde
2014-10-08 14:01 ` David Jander
2014-10-09 10:37 ` David Jander
2014-10-01 9:19 ` David Jander
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