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Date: Wed, 3 Mar 2010 18:59:31 -0800
Message-ID: <be233a491003031859s7d409e11k599a319ce04b7696@mail.gmail.com>
Subject: Re: [PATCH] hpet: factor timer allocate from open
From: Magnus Lynch <maglyx@gmail.com>
To: Clemens Ladisch <clemens@ladisch.de>
Cc: venkatesh.pallipadi@intel.com, vojtech@suse.cz,
       linux-kernel@vger.kernel.org
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On Mon, Mar 1, 2010 at 1:59 AM, Clemens Ladisch <clemens@ladisch.de> wrote:
>> @@ -438,6 +469,17 @@ hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
>>  {
>>        struct hpet_dev *devp;
>>
>> +       switch (cmd) {
>> +       case HPET_INFO:
>> +               break;
>> +       default:
>> +               {
>> +                       int r = hpet_alloc_timer(file);
>
> Applications might want to use HPET_INFO to find out which timer they
> got, so I think the driver cannot avoid allocating a timer in this case.

Oh, I missed commenting this in my first reply. I chose to make
HPET_INFO specify timer -1 in case a timer isn't currently allocated.
You think there are extant cases of programs depending on open then
immediate HPET_INFO having a timer allocated? Seems obscure to me. If
so I can change that. I did add the explicit form of allocating timers
to accomodate such a case hypothetically (open, allocate timer, get
info).