Re: USB Driver uhci.c legacy mode

[Vladimir 'φ-coder/phcoder' Serbinenko]

On 07/27/2010 06:54 AM, D, Eshwar (Eshwar) wrote:
> HI,
>    I would like to contribute for EHCI driver.. Let me know if any space is 
> available for me... By the way I already spoke to Ales & Vladimir... 
>
>   
AFAIK nobody else is working on EHCI even if it's important.
Unfortunately I can't give you write access to offical bzr both because
of legal and technical reasons. I recommend creating an account at
launchpad. Also I recommend sending early patches to ML even if they
don't work so nobody gets an impression that you've just disappeared and
so we can comment early on your code. Some mistakes may go unnoticed on
some hardware but be fatal on some other hardware.
> Regards
> Eshwar
>
>   
>> -----Original Message-----
>> From: address@hidden 
>> [mailto:address@hidden
>> ] On Behalf Of Aleš Nesrsta
>> Sent: Saturday, July 24, 2010 11:45 PM
>> To: The development of GNU GRUB
>> Subject: Re: USB Driver uhci.c legacy mode
>>
>> Hi, I am sorry to be late with answer, unfortunately, I have 
>> few time during our school holidays...
>> To Your questions, chronologically:
>>
>>     
>>> how would i surely know that grub usb driver would not work on this 
>>> platform?
>>>       
>> None of current USB drivers will work if Your PC is EHCI-only 
>> PC. One way how to find it I described before (via lspci). 
>> But You have to be sure You have properly set USB part in 
>> BIOS (or You should try all possible USB BIOS configurations 
>> etc. ...).
>> Another way is for example to find detailed specification of 
>> Your laptop HW. I tried shortly to find something on Internet 
>> but there are specifications like "USB 2.0 compatible" etc. 
>> and the same specifications are often used also for 
>> controllers which includes OHCI/UHCI USB 1.0 too - so, I am not sure.
>>
>> Definitely You can find it by check of HCSPARAMS register of EHCI.
>> According EHCI specification, this 32-bit register should be 
>> at USBBASE
>> + 08h (USBBASE pointer should be in PCI configuration registers at PCI
>> base + 10h).
>> Bits 15:12 of HCSPARAMS should be nonzero. If You find zero 
>> there, You have EHCI-only controller (without OHCI/UHCI 
>> companion controllers) in Your PC, i.e., Your USB controller 
>> is currently not directly supported by GRUB :-(
>>
>>
>>     
>>> jonatan perry wrote:
>>> i have another question regarding grub usb ehci support - is such 
>>> support under development? is such support are planned to 
>>>       
>> be? what is 
>>     
>>> the current status?
>>>       
>> Hm, I am not the right person to answer these questions 
>> properly, I am not coordinator... Maybe Vladimir Serbinenko 
>> will answer it better.
>>
>> >From my point of view:
>> - Development of EHCI is planned.
>> - Current status of EHCI driver development - probably 0%. 
>> AFAIK, nobody is currently working on EHCI support. But I 
>> could be wrong and it can change at any time.
>>
>> I was asked some months ago by Vladimir, if I am interesting 
>> also in EHCI. I answered "no" originally - because I thought 
>> that all EHCI controllers have also companion OHCI/EHCI 
>> controllers and speed of USB
>> 1.0/1.1 devices is not critical for GRUB (because it is "only"
>> bootloader...).
>> I changed point of view from some reasons short time ago. I 
>> wanted, at least, find why some devices are not working on my 
>> EHCI/UHCI port - it looks like problem is on powering of 
>> ports (but UHCI has no power control of its ports - or, at 
>> least, it is not written in UHCI specification...). I think 
>> that this problem is maybe somewhere in EHCI, so I want to 
>> start some experiments with EHCI.
>>
>> But:
>> - GRUB USB development is currently focused on enhancement 
>> and debugging of current USB drivers and related code - for 
>> example hot-plugging and hub support. I want to help with 
>> these things first before doing something new (and generate 
>> new bugs...).
>> - EHCI is different and more complex than OHCI/UHCI
>> - it looks like I will too busy in next weeks/months. So, if 
>> EHCI support will depend only on me, it will take very long 
>> time... Maybe somebody else will start development of EHCI 
>> driver sooner (or maybe it is started?)...?
>>
>> With regards
>> Ales
>>
>>
>>
>>
>> _______________________________________________
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>>
>>     
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>   


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko

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