From: Wolfram Sang <w.sang@pengutronix.de>
To: "Shawn.Dong" <shawn.dong.cx@gmail.com>
Cc: linux-mmc@vger.kernel.org
Subject: Re: [PATCH]mmc: sdhci: use udelay instead of mdelay for some cases
Date: Thu, 27 Oct 2011 07:15:32 +0200 [thread overview]
Message-ID: <20111027051532.GA28387@pengutronix.de> (raw)
In-Reply-To: <20111027041851.GA18442@gmail.com>
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Hi,
On Thu, Oct 27, 2011 at 12:18:53PM +0800, Shawn.Dong wrote:
> sdhci_set_clock or sdhci_reset or sdhci_send_command may be used in
> critical region which is protected by spin_lock_irqsave. Thus, these
> functions will delay the responsing of the kernel interrupts.
Yes, so this needs to be improved, not the delay values.
> So in this case, using a mdelay will cause unnecessary latency. Our
> hardware, in most case will not cause 1ms to finish its job. Using
> udelay instead can reduce it.
Could you guarantee this for all other SDHCI hardware out there as well?
Regards,
Wolfram
--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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next prev parent reply other threads:[~2011-10-27 5:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-27 4:18 [PATCH]mmc: sdhci: use udelay instead of mdelay for some cases Shawn.Dong
2011-10-27 5:09 ` Barry Song
2011-10-27 5:15 ` Wolfram Sang [this message]
2011-10-27 5:09 ` Shawn.Dong
2011-10-27 6:02 ` Wolfram Sang
2011-11-04 8:24 ` Shawn.Dong
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