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From: David Miller <davem@davemloft.net>
To: mroos@linux.ee
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH] tms380tr: fix long delays in initialization
Date: Mon, 04 Oct 2010 09:42:54 -0700 (PDT)	[thread overview]
Message-ID: <20101004.094254.35052481.davem@davemloft.net> (raw)
In-Reply-To: <alpine.SOC.1.00.1010041135060.12325@math.ut.ee>

From: Meelis Roos <mroos@linux.ee>
Date: Mon, 4 Oct 2010 11:39:02 +0300 (EEST)

>> > tms380tr driver tries to use udelay (meaning busy loop) for several half 
>> > second delays during hardware initialization. Crazy overly long busy 
>> > wait delays mean no delay at all so driver initialization fails without 
>> > waiting. Fix it by using msleep() for long delays and leave it to 
>> > udelay() for short delays.
>> > 
>> > Signed-off-by: Meelis Roos <mroos@linux.ee>
>> 
>> You can't use msleep() here because this code can be invoked
>> from interrupts and thus cannot sleep.
> 
> I checked these two functions that contain long delays that I changed - 
> tms380tr_bringup_diags() and tms380tr_init_adapter() - to be called only 
> from tms380tr_chipset_init() that is only called from tms380tr_open() so 
> no call paths from interrupts AFAICS. Short delyas from interrupt 
> context are not changed in any way, they still use udelay().

tms380tr_init_adapter() gets called from tms380tr_chk_irq() which is
invoked from the interrupt handler.

  reply	other threads:[~2010-10-04 16:42 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-03 19:34 [PATCH] tms380tr: fix long delays in initialization Meelis Roos
2010-10-04  3:01 ` David Miller
2010-10-04  8:39   ` Meelis Roos
2010-10-04 16:42     ` David Miller [this message]
2010-10-04 21:15       ` Meelis Roos
2010-10-04 21:33         ` David Miller

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