Attention is currently required from: Nico Huber, Angel Pons. Peter Farley has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/63798 )
Change subject: ft2232_spi: Reduce read size for FT232H ......................................................................
Patch Set 1:
(1 comment)
Commit Message:
https://review.coreboot.org/c/flashrom/+/63798/comment/826d7b87_7e23e539 PS1, Line 9: FT232H-based devices are unable to read over 256 bytes of flash in one
One more general thought: Is there any other software running that might try to access the FT232H device? any kernel driver or anything using libusb should not cause any trouble, but who knows...
The only thing I notice is that when the device is attached, it gets associated with the `ftdi_sio` driver. But after `flashrom` takes control, it appears to release it. Unloading and blacklisting that module doesn't make a difference either.
What would be interesting is if it always stops at that point or if always on a 4096B boundary. I guess it would suffice to re-run the capture and check if/how the number of frames changes. The 4096B these URBs request are probably the default read chunk size of libftdi. So lowering this (maybe to an odd multiple of 512, e.g. 1536) to see if it still fails after a full chunk might be interesting as well. If it does it would further increase my suspicion that it's a soft- ware issue.
Testing it some more, even without changing the chunk size, the number of received packets is not constant. It seems I might have been lucky getting a full 64K yesterday, today I am seeing anywhere between 0 and 5 4080B blocks.
Due to its apparent randomness, I can't say definitively, but decreasing the chunk size from 4096 to 1536 does increase the average RX packet count (over only 5 iterations), from 2 to 8.