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From: Thomas Gleixner <tglx@linutronix.de>
To: Jacky Lam <lamshuyin@gmail.com>
Cc: frank.rowand@am.sony.com, Stanislav Meduna <stano@meduna.org>,
	"linux-rt-users@vger.kernel.org" <linux-rt-users@vger.kernel.org>
Subject: Re: Protection of critical section in PREEMPT_RT
Date: Mon, 4 Feb 2013 11:40:53 +0100 (CET)	[thread overview]
Message-ID: <alpine.LFD.2.02.1302041138400.11905@ionos> (raw)
In-Reply-To: <CAHX1yNQgJXM292q1DWXLdQiR_BK5jZ-d+QHVoEEgksQm04YU6g@mail.gmail.com>

Jacky,

On Mon, 4 Feb 2013, Jacky Lam wrote:

> Thanks.

Please stop top posting!
 
> I finally find that if I disable interrupt during ata_qc_issue() in
> libata-scsi.c, my sata driver works without any problem.

This is wrong. Which driver are you taling about ?
 
> But I find USB EHCI driver is more complicated. Kernel crashes every
> where when RT is turned on. It seems whenever the stack  spin_lock
> ehci->lock and interrupt comes at that moment, kernel will be crashes.
> The reason is EHCI interrupt handler will also take the same lock. If
> my point of view, USB stack seems no PREEMPT_RT safe. Is it correct?
> Am I miss anything?

Probably. First of all you don't tell us which driver you are
using. And w/o seing the code and the output of the kernel crash, we
can't help you at all.

Thanks,

	tglx

  reply	other threads:[~2013-02-04 10:41 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-22  3:29 Protection of critical section in PREEMPT_RT Jacky Lam
2013-01-22 10:24 ` Stanislav Meduna
2013-01-31  9:27   ` Jacky Lam
2013-01-31 19:52     ` Frank Rowand
2013-02-04  7:27       ` Jacky Lam
2013-02-04 10:40         ` Thomas Gleixner [this message]
2013-02-05  1:40           ` Jacky Lam
2013-02-05 10:05             ` Thomas Gleixner
2013-02-06  1:59               ` Jacky Lam
2013-02-06  8:56                 ` Stanislav Meduna
2013-02-13 11:31                 ` Thomas Gleixner

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