Re: [PATCH v2] usb: serial: Repair FTDI FT232R bricked eeprom

From: Hector Martin
Date: Thu Sep 10 2020 - 05:59:30 EST

On 10/09/2020 18.52, James Hilliard wrote:
So I'm having trouble coming up with a reliable way to fix this in userspace,
I've already got quite a few moving parts there as is and most of what I
come up with seems like it would not work reliably, at least for automatically
repairing the eeprom.

I'm confused as to why this is hard to fix in userspace. You already said you have userspace code binding to the proper VID/PID, so your code won't find the bricked device. Then it's just a matter of having a udev rule run the unbricker when it detects the bad device (which should issue a USB reset when it's done reprogramming, making the device appear as the right VID/PID), thus effectively doing the same thing the kernel does. If this is embedded and not using udev, then substitute whatever equivalent you have. If you're polling for the device at runtime instead and don't have a device manager, just poll for the VID 0 device too and apply the fix.

I can't think of a scenario where this would be difficult to fix in userspace...

Hector Martin (hector@xxxxxxxxxxxxxx)
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