From: Wolfgang Grandegger <wg@grandegger.com>
To: David Miller <davem@davemloft.net>
Cc: masa-korg@dsn.okisemi.com, andrew.chih.howe.khor@intel.com,
sameo@linux.intel.com, margie.foster@intel.com,
netdev@vger.kernel.org, yong.y.wang@intel.com,
linux-kernel@vger.kernel.org, socketcan-core@lists.berlios.de,
mkl@pengutronix.de, chripell@fsfe.org,
morinaga526@dsn.okisemi.com, meego-dev@meego.com,
kok.howg.ewe@intel.com, joel.clark@intel.com, qi.wang@intel.com
Subject: Re: [MeeGo-Dev][PATCH v3] Topcliff: Update PCH_CAN driver to 2.6.35
Date: Wed, 06 Oct 2010 11:12:52 +0200 [thread overview]
Message-ID: <4CAC3D94.9010408@grandegger.com> (raw)
In-Reply-To: <20101005.200904.71120150.davem@davemloft.net>
On 10/06/2010 05:09 AM, David Miller wrote:
> From: "Masayuki Ohtake" <masa-korg@dsn.okisemi.com>
> Date: Wed, 6 Oct 2010 12:07:15 +0900
>
>> Does your mail mean, for accepting upstream, NAPI is essential for
>> CAN driver ?
>
> It is up to the CAN maintainers :-)
Well, our SJA1000 reference driver does still not use NAPI. But NAPI is
for CAN especially useful to avoid the infamous *bus error irq
flooding*, which may hang low end systems if the interrupts are handled
in the IRQ context. Ohtake, if your system can handle well such CAN bus
error irq storms at 1MB/s, then NAPI is *not* a must to have. Anyway, as
you are at it, I also suggest to use NAPI right from the beginning.
Wolfgang.
WARNING: multiple messages have this Message-ID (diff)
From: Wolfgang Grandegger <wg-5Yr1BZd7O62+XT7JhA+gdA@public.gmane.org>
To: David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
Cc: andrew.chih.howe.khor-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org,
sameo-VuQAYsv1563Yd54FQh9/CA@public.gmane.org,
margie.foster-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
yong.y.wang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
masa-korg-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org,
mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org,
joel.clark-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
morinaga526-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org,
meego-dev-WXzIur8shnEAvxtiuMwx3w@public.gmane.org,
kok.howg.ewe-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
chripell-VaTbYqLCNhc@public.gmane.org,
qi.wang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org
Subject: Re: [MeeGo-Dev][PATCH v3] Topcliff: Update PCH_CAN driver to 2.6.35
Date: Wed, 06 Oct 2010 11:12:52 +0200 [thread overview]
Message-ID: <4CAC3D94.9010408@grandegger.com> (raw)
In-Reply-To: <20101005.200904.71120150.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
On 10/06/2010 05:09 AM, David Miller wrote:
> From: "Masayuki Ohtake" <masa-korg-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org>
> Date: Wed, 6 Oct 2010 12:07:15 +0900
>
>> Does your mail mean, for accepting upstream, NAPI is essential for
>> CAN driver ?
>
> It is up to the CAN maintainers :-)
Well, our SJA1000 reference driver does still not use NAPI. But NAPI is
for CAN especially useful to avoid the infamous *bus error irq
flooding*, which may hang low end systems if the interrupts are handled
in the IRQ context. Ohtake, if your system can handle well such CAN bus
error irq storms at 1MB/s, then NAPI is *not* a must to have. Anyway, as
you are at it, I also suggest to use NAPI right from the beginning.
Wolfgang.
next prev parent reply other threads:[~2010-10-06 9:11 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-24 10:24 [MeeGo-Dev][PATCH v3] Topcliff: Update PCH_CAN driver to 2.6.35 Masayuki Ohtak
2010-09-27 8:38 ` Wolfgang Grandegger
2010-09-27 8:38 ` Wolfgang Grandegger
2010-09-30 9:10 ` Wolfgang Grandegger
2010-09-30 9:10 ` Wolfgang Grandegger
2010-09-30 18:50 ` David Miller
2010-09-30 18:50 ` David Miller
2010-10-01 10:02 ` Masayuki Ohtake
2010-10-01 10:02 ` Masayuki Ohtake
2010-10-01 12:40 ` Wolfgang Grandegger
2010-10-01 12:40 ` Wolfgang Grandegger
2010-10-05 10:21 ` Masayuki Ohtake
2010-10-05 10:21 ` Masayuki Ohtake
2010-10-05 11:08 ` Marc Kleine-Budde
2010-10-05 12:09 ` Masayuki Ohtake
2010-10-05 12:09 ` Masayuki Ohtake
2010-10-05 18:45 ` David Miller
2010-10-05 18:45 ` David Miller
2010-10-06 3:07 ` Masayuki Ohtake
2010-10-06 3:07 ` Masayuki Ohtake
2010-10-06 3:09 ` David Miller
2010-10-06 3:09 ` David Miller
2010-10-06 9:12 ` Wolfgang Grandegger [this message]
2010-10-06 9:12 ` Wolfgang Grandegger
2010-10-12 7:09 ` Masayuki Ohtake
2010-10-12 7:09 ` Masayuki Ohtake
2010-10-12 7:42 ` Wolfgang Grandegger
2010-10-12 7:42 ` Wolfgang Grandegger
2010-10-12 7:56 ` Marc Kleine-Budde
2010-10-12 7:56 ` Marc Kleine-Budde
2010-10-13 4:23 ` Masayuki Ohtake
2010-10-13 4:23 ` Masayuki Ohtake
2010-10-13 7:38 ` Marc Kleine-Budde
2010-10-13 7:38 ` Marc Kleine-Budde
2010-10-13 10:09 ` Masayuki Ohtake
2010-10-13 10:09 ` Masayuki Ohtake
2010-10-13 11:08 ` Wolfgang Grandegger
2010-10-13 11:08 ` Wolfgang Grandegger
2010-10-13 12:05 ` Masayuki Ohtake
2010-10-13 12:05 ` Masayuki Ohtake
-- strict thread matches above, loose matches on Subject: below --
2010-09-24 10:24 Masayuki Ohtak
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