> -----Original Message----- > From: Greg KH [mailto:greg@xxxxxxxxx] > Sent: Monday, September 28, 2015 10:12 AM > To: Rob Groner <rgroner@xxxxxxx> > Cc: Valdis.Kletnieks@xxxxxx; kernelnewbies@xxxxxxxxxxxxxxxxx > Subject: Re: [PATCH] 8250_pci: Prevent Exar/RTD Boards from binding. > > On Mon, Sep 28, 2015 at 08:53:49AM -0400, Rob Groner wrote: > > On Fri, 2015-09-25 at 17:45 -0700, Greg KH wrote: > > > On Fri, Sep 25, 2015 at 03:21:46PM -0400, Rob Groner wrote: > > > > > > > > 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:greg@xxxxxxxxx] > > > > >>> Sent: Friday, September 25, 2015 2:37 PM > > > > >>> To: Rob Groner <rgroner@xxxxxxx> > > > > >>> Cc: Valdis.Kletnieks@xxxxxx; kernelnewbies@xxxxxxxxxxxxxxxxx > > > > >>> 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: Valdis.Kletnieks@xxxxxx > > > > >>>>> [mailto:Valdis.Kletnieks@xxxxxx] > > > > >>>>> Sent: Friday, September 25, 2015 12:48 PM > > > > >>>>> To: Rob Groner <rgroner@xxxxxxx> > > > > >>>>> Cc: kernelnewbies@xxxxxxxxxxxxxxxxx > > > > >>>>> 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 > > > > > > At first glance, the driver looks pretty good. Let me do a bit of > > > cleanup on it for mostly coding style changes and removing some old > > > api support and see what the patch is. > > > > > > Would you mind testing it if I make a patch, given that I don't have > > > the hardware and you do? :) > > > > > > thanks, > > > > > > greg k-h > > > > I don't mind in the slightest, it's the least I can do! I've got my > > test station ready and have 3 different CPUs I can test with. Being > > new to the whole patching thing, I may need a few hints and helps to > > make sure I apply the patch correctly... > > > > Will it be showing up here in kernel newbies mailing list, or > > linux-serial, or other? > > How about let's take it to linux-serial, and I'll cc: you as well, that's the proper > place for this. > > Note, the driver does do some "odd" things in that it has some "custom" > ioctls for unknown reasons, and it grabs a major number of another driver, > both things that I can't accept upstream. It also seems to duplicate a lot of > existing code, so maybe it doesn't really need to be a separate driver. I'll dig > around in it and see what I can come up with, give me a week or so... > > thanks, > > greg k-h I know you're incredibly busy, so I added as much "so" to the week as I could. Any way I can help with this endeavor, other than testing? Thanks, Rob Groner _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
