On 09/25/2015 03:14 PM, Greg KH wrote:
> On Fri, Sep 25, 2015 at 07:08:32PM +0000, Rob Groner wrote:
>>> -----Original Message-----
>>> From: Greg KH [mailto:[email protected]]
>>> Sent: Friday, September 25, 2015 2:37 PM
>>> To: Rob Groner <[email protected]>
>>> Cc: [email protected]; [email protected]
>>> Subject: Re: [PATCH] 8250_pci: Prevent Exar/RTD Boards from binding.
>>>
>>> On Fri, Sep 25, 2015 at 05:37:03PM +0000, Rob Groner wrote:
>>>>> -----Original Message-----
>>>>> From: [email protected] [mailto:[email protected]]
>>>>> Sent: Friday, September 25, 2015 12:48 PM
>>>>> To: Rob Groner <[email protected]>
>>>>> Cc: [email protected]
>>>>> Subject: Re: [PATCH] 8250_pci: Prevent Exar/RTD Boards from binding.
>>>>>
>>>>> On Fri, 25 Sep 2015 11:46:29 -0400, Rob Groner said:
>>>>>> Serial boards made by RTD using the Exar XR17V358 chip rely on the
>>>>>> extra capabilities of the Exar-provided driver to allow
>>>>>> configuration of the board.  When support for the Exar chip was
>>>>>> added to the kernel 8250_pci driver, this then prevented easy use
>>>>>> of the board by customers for anything other than standard serial usage
>>> in RS232 mode.
>>>>> Was it your intent to also prevent the use of this board in standard
>>>>> serial usage in RS232 mode (which I'd expect is the most common use
>>> case)?
>>>> That is a byproduct of giving the non-average user the ability to
>>>> reconfigure their board.  This will basically move us back to pre-3.8,
>>>> where the customer would simply have to insmod the provided Exar
>>>> driver.  The small inconvenience to that more common user seems (to us
>>>> in Tech Support) outweighed by the much greater inconvenience to the
>>>> user who wants to reconfigure.
>>> Where is the exar driver, in the kernel already?
>>>
>>> confused,
>> I'm sorry for the confusion.  Let me summup:
>>
>> We produce a serial port board that uses the Exar XR17V358 chip.  The board 
>> features a jumperless configuration so that to change the board from RS232 
>> to RS422/RS485, you use the GPIO available on the Exar chip, via the Exar 
>> driver.  That driver is provided by Exar (from their website, and repackaged 
>> on our website and with the board).
>>
>> Recently, we began to hear from customers who purchased the board but could 
>> not get the driver to find the board (and thus could not reconfigure it, nor 
>> use the non-standard high baud rates the chip is capable of).  We discovered 
>> that in 3.8, support for the Exar chip was added to the 8250_pci driver, 
>> thus binding it to the kernel.
>>
>> Until (and probably if) Exar decides to submit their driver to the kernel, 
>> then it leaves us with a problem that we didn't have prior to 3.8...namely 
>> that the board won't do what it is advertised to do unless the customer 
>> rebuilds the kernel (that is the only supported workaround from Exar).  The 
>> only other workaround we know of (unbind) has met with mixed success which I 
>> won't go into unless you want me to, and is already resisted by some 
>> customers.
>>
>> The goal of this patch is to get to a point where a customer can install 
>> Linux and have full use of this RTD board (using the driver Exar/RTD 
>> provides).  No one who has an RTD board is going to feel this is an 
>> inconvenience.
> Can you point me at the driver and I'll be glad to add it to the kernel
> so that the proper driver will bind to the device and this will
> not be an issue for users?
>
> thanks,
>
> greg k-h
That would be WONDERFUL.

https://www.exar.com/common/content/document.ashx?id=20121

Thank you,

Rob Groner


_______________________________________________
Kernelnewbies mailing list
[email protected]
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

Reply via email to