netdev - Re: [PATCH] tms380tr: fix long delays in initialization

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Message-Id: <20101004.094254.35052481.davem@davemloft.net>
Date:	Mon, 04 Oct 2010 09:42:54 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	mroos@...ux.ee
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH] tms380tr: fix long delays in initialization

From: Meelis Roos <mroos@...ux.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@...ux.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.
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