I added the patch, and tried it out. When the network hangs, I am able to revive it with ALT-SYSRQ-Q. The debug log shows these entries:
Jan 12 19:22:57 behemoth kernel: SysRq: <0> NR Log Phy Mask Trig IRR Pol Stat Dest Deli Vect:
Jan 12 19:22:57 behemoth kernel: Before:
Jan 12 19:22:57 behemoth kernel:  00 003 03  0    1    1   1   1    1    1    99
Jan 12 19:22:57 behemoth kernel: After switching to edge:
Jan 12 19:22:57 behemoth kernel:  00 003 03  0    0    1   1   1    1    1    99
Jan 12 19:22:57 behemoth kernel: After switch back:
Jan 12 19:22:57 behemoth kernel:  00 003 03  0    1    1   1   1    1    1    99
-- 
  WWWWW      _______________________
 ## o o\    /     Frank de Lange     \
 }#   \|   /                          \
  ##---# _/     <Hacker for Hire>      \
   ####   \      +31-320-252965        /
           \    frank@unternet.org    /
            -------------------------
 [ "Omnis enim res, quae dando non deficit, dum habetur
    et non datur, nondum habetur, quomodo habenda est."  ]
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