Re: cd-tray immediately closed after it has been opened

[Christian Krause <chkr@plauener.de>]

Hi Kay,

Kay Sievers wrote:
> On Mon, Jul 28, 2008 at 10:48, Christian Krause <chkr@plauener.de> wrote:
>   
>> David Zeuthen wrote:
>>     
>>> On Sun, 2008-07-27 at 21:19 +0200, Christian Krause wrote:
>>>
>>>       
>>>> Before this checkin, vol_id was only called for partitioned devices and
>>>> so the CD tray stayed open.
>>>>
>>>>         
>>> Probably vol_id needs to use O_NONBLOCK when opening sr devices. Does
>>> that fix it?
>>>
>>>       
>> Yes, indeed using a patch like this:
>>
>> diff --git a/extras/volume_id/vol_id.c b/extras/volume_id/vol_id.c
>> index 5c4e05d..3dc9f95 100644
>> --- a/extras/volume_id/vol_id.c
>> +++ b/extras/volume_id/vol_id.c
>> @@ -224,7 +224,7 @@ int main(int argc, char *argv[])
>>               goto exit;
>>       }
>>
>> -       fd = open(node, O_RDONLY);
>> +       fd = open(node, O_RDONLY | O_NONBLOCK);
>>       if (fd < 0) {
>>               fprintf(stderr, "%s: error opening volume\n", node);
>>               rc = 2;
>>
>> fixes the problem, too. But it looks like that this is discouraged:
>>
>> http://gitweb.freedesktop.org/?p=hal.git;a=commit;h-ab6d1b27a160895e99f3a7111a78aff68baff3
>>     
>
> Just to check if its the kernel that closes the tray on open(), can you set:
>   /proc/sys/dev/cdrom/autoclose
> to "0" and try again?
>   
I've tried it out with a small test program which just does an 
open("/dev/sr0", O_RDONLY)
and additionally with the complete udev/hal/... stack:

If autoclose = 0 then the tray is not closed otherwise it is (without 
O_NONBLOCK).
If O_NONBLOCK is used, the tray is not closed, even if autoclose = 0. So 
yes, it is the kernel which closes the tray.


Best regards,
Christian