[Nut-upsdev] blazer_usb: compatibility with Ippon BackPro UPSes (Phoenix Power Co., Ltd usb-to-serial controller)

[Alexey Loukianov]

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07.01.2010 11:55, Arjen de Korte wrote:
> Citeren Alexey Loukianov <mooroon2 at mail.ru>:

> Not easily. We don't have access to all these devices. Most of the  
> reports about drivers being broken are from users from the field, from  
> whom we usually never hear again until something breaks. I'm not  
> willing to take the risk to break this driver, if there are good  
> alternatives around.
> 

Again: we do not need to break existing phoenix driver. Current implementation
of blazer_usb allows addition of any new subdriver that can simply co-exist with
existing ones. Why not to add new subdriver and name it - say - ipponrhel4?
It will not break compatibility with the devices that are already working
normally but will present people on CentOS4/RHEL4 with an alternative variant in
case their device is not working correctly with original phoenix subdriver.

>> but when using libusb-0.1.8 that is the stock version for RHEL4
>> reading in 8-bytes chunks makes phoenix usb-to-serial device in Ippon UPSes
>> hang.
> 
> In that case, we don't support this device with libusb-0.1.8. I don't  
> think we should consider patches that might break other devices that  
> are supported now, to add support for a library that is almost six  
> years old. The fact that even libusb-0.1.12 is almost four years old  
> tells me that we should probably up our minimum libusb requirements to  
> that instead.
> 

That is correct, but there is one bad consequence when taking such approach. EOL
for RHEL4 (and thus CentOS4, Scientific Linux 4 and all the other RHEL4 clones)
is Feb-2012. It means that RHEL4 and CentOS4 will be actively used for at least
next two years. People who are not subscribers of paid Red Hat or CentOS network
support will easily bump libusb version up to 0.1.12 and will be happy. Rest
will be forced either to lost paid support services from RedHat/CentOS (support
services agreement specifically denies updating of any core system component -
and libusb is one of such components - to a version not supplied/supported by
RedHad), or not to use the device they might be able to use normally in case NUT
will incorporate special patch for libusb-0.1.8-RHEL4 compatibility. Me
personally isn't affected by this at all: I've got no problems in patching NUT
myself and building up special binary RPM package for the servers I administer.
People in question are all that system administrators worldwide that are still
using RHEL4/CentOS and are experiencing troubles with their Ippon (and possibly
others) UPSes when connecting them to a server through USB interface.

- -- 
Best regards,
Alexey Loukianov                          mailto:mooroon2 at mail.ru
System Engineer,                            Mob.:+7(926)218-1320
*nix Specialist

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