Scanning mystery

[Steven Stern]

If I scan from my HP 8500A using the automatic document feeder and
GScan2PDF, the scanner feeds paper but nothing appears in the program
(from either side of the page).  If I have it scan from the glass, then
scanning works, but I have to manually feed pages.

If I scan via hp-scan --adf, scanning works as expected with the
automatic document feeder.

Both programs use the same device, Using device
hpaio:/usb/Officejet_Pro_8500_A910?serial=CN16HCR00K

Any ideas?


-- 
-- Steve