From: Matt Sealey <matt@genesi-usa.com>
To: Matteo Fortini <m.fortini@selcomgroup.com>
Cc: linuxppc-embedded@ozlabs.org
Subject: Re: MPC512x SPI very high cpu load
Date: Thu, 20 Nov 2008 13:39:54 -0600 [thread overview]
Message-ID: <4925BD0A.3030307@genesi-usa.com> (raw)
In-Reply-To: <49243010.9070106@selcomgroup.com>
Matteo Fortini wrote:
> Hi,
> we're using the latest denx tree on an mpc512x, and we have a
> touchscreen on the spi which is talking at 100kHz.
>
> The polling frequency is 5ms and we transmit around 20 bytes per poll.
>
> If we keep the touchscreen pressed, cpu utilization goes to 70% for the
> spi task. This is quite strange, since I thought the mpc512x would be
> using DMA to feed the PSC FIFOs.
If the SPI driver isn't using DMA then, it's not using DMA.
--
Matt Sealey <matt@genesi-usa.com>
Genesi, Manager, Developer Relations
prev parent reply other threads:[~2008-11-20 19:45 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-19 15:26 MPC512x SPI very high cpu load Matteo Fortini
2008-11-20 19:39 ` Matt Sealey [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4925BD0A.3030307@genesi-usa.com \
--to=matt@genesi-usa.com \
--cc=linuxppc-embedded@ozlabs.org \
--cc=m.fortini@selcomgroup.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.