On Fri, Apr 18, 2014 at 03:37:53PM -0700, Larry Baker wrote: > > What about my question of vendor supported vs. reverse engineered > USB serial drivers. If there is a chip with (better) vendor Linux > driver support, I can complain to them and they can fix it instead > of us. So here's the problem with vendor supported drivers. More often than not, it will be for some distribution kernel, and not something which can be contributed to the upstream kernel. Very often, it was whatever kernel version the last Major Customer of said vendor was using, and the work was done by a contractor (or by an engineer who is no longer with the vendor), and the driver can't be easily ported to some other kernel. You yourself mentioned using a 2.6.32 CentOS kernel. The 2.6.32 kernel was released some four years ago, in 2010. Most of the community developers work on the upstream kernel; we have trouble remembering what was in a kernel from your years ago. (``In the internet, two years is infinity'') The more enlightened companies these days will insist that the peripheral vendor will provide if there is a open source driver which has been contributed to the upstream kernel. That way, eventually all of the distributions can get the same driver, and we don't have to worry about multiple out-of-tree drivers only barely supported by the vendors (because the contractor or the employee has moved on). This works well if you are an IBM or a HP, or if you are Samsung or a LG, and you can say, "we're only going to buy millions of dollars of your serial chip / scsi controller / whatever if your driver gets submitted upstream. > If you were to buy a USB-to-Serial adapter, which chip would > you buy? So it's been a long time since I've had to use an RS-232 device (which is why I stepped down as the serial maintainer years ago), but speaking generally, what you want is a chip which is actively vendor supported, and in the mainline source tree. So if I were looking, I'd probably do some looking at git commits for the USB serial drivers, and see which ones seem to be actively maintained by someone who is clearly either working for one of the vendors, or is actively being supported by one the vendors. Good luck, - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
