Re: [Xenomai-help] LATENCIES > 100 us or CRASH WITH X (with joints pieces)

[Jean-Luc Pamart <jlpamart@domain.hid>]

Jan Kiszka a écrit :
> Jean-Luc Pamart wrote:
>   
>> Jan Kiszka a écrit :
>>     
>>> Jean-Luc Pamart wrote:
>>>  
>>>       
>>>> Hello
>>>>
>>>> I am a newbie with Xeno. My goal for the beginning of 2007 is to launch
>>>> a project for 4 french studiants : a box with Linux embedded and a usb
>>>> camera. The embedded application will analyse the movies in Real time
>>>> and lead a mobile machine with CAN-BUS.
>>>> Now i play with Xeno for my knowledge (without specific hardware) :  a
>>>> little linux installed in a usb key with a little embedded distrib
>>>>
>>>> - vanilla kernel 2.6.16 with patch for usb [.config is joint]
>>>> - Xenomai 2.1.2
>>>> - essentially BusyBox
>>>> - for xenomai : only "latency" directory and libs in usr/libs
>>>> I have checked "SMI woraround" for the kernel.
>>>> In BIOS I have UNchecked  "legacy usb".
>>>>
>>>>
>>>> my Desktop PC (a AMD ATHLON) can boot with this little vanilla kernel
>>>> and
>>>> 1/ a little embedded distrib of my own
>>>>
>>>> OR
>>>>
>>>> 2/ a complete mandrake 9.1 on a partition of a classic hard disk
>>>>
>>>> I have 2 differents problems when I lauch this :
>>>>
>>>> 1/ with the linux embedded directories on the usb key
>>>> high latency > 100 us are ok ? perhaps usb work is not compatible
>>>> with RT ?
>>>>     
>>>>         
>>> Try loading the standard USB drivers (at least uhci_hcd) if they aren't
>>> yet. Actually, I've seen boxes (granted, they were far older) where I
>>> had to switch legacy USB *on* to avoid disturbances. In any case, check
>>> carefully if you followed all tips in TROUBLESHOOTING regarding latency
>>> issues (APM, ACPI, etc.).
>>>
>>>  
>>>       
>>>> 2/ with the complete mandrake 9.1 :
>>>> it crashes X after 1 or few minutes.
>>>> What is the relation between X and Xenomai ?
>>>> Is Xenomai compatible with X ?
>>>>     
>>>>         
>>> Yes, as long as X is not playing against us, e.g. by hard-disabling
>>> interrupts or doing (too) evil things on the buses. Any non-GPL driver
>>> in this game here (NVidia&Co)? Better avoid this. Also try to disable
>>> accelerated mode in your X setup to see if things improve.
>>>
>>> Jan
>>>
>>>   
>>>       
>> Ok , for the box with a vanilla kernel I will try the differents
>> possibilities. Actually i disable
>> a max of things ...
>>
>> For the box with X : the big surprise was : very goods latencies
>> (comparativeley with no X !!)
>> Why ????
>> (Before crashing)
>>     
>
> If it turns out to be an ACPI/APM issue, X may keep your box busier than
> plain text mode, thus avoid those latency peaks by keeping it out of
> certain sleep modes - well, an attempt to explain something I can't with
> the currently available information...
>
>   
>> for crashing
>> I 'll verify theses 2 points :
>> nvidia driver
>> accelerated mode  : Is it a x server setup ?
>>
>>     
>
> See Gilles' reply => XF86Config.
>
> Jan
>
>
> PS: Don't forget to reply-to-all.
>
>   
OK !

	

	
		
___________________________________________________________________________ 
Yahoo! Mail réinvente le mail ! Découvrez le nouveau Yahoo! Mail et son interface révolutionnaire.
http://fr.mail.yahoo.com