On Thu, Jan 05, 2023 at 01:58:48PM -0800, Linus Torvalds wrote: > On Thu, Jan 5, 2023 at 6:48 AM Jason A. Donenfeld <Jason@xxxxxxxxx> wrote: > > > > TPM 1's support for its hardware RNG is broken across system suspends, > > due to races or locking issues or something else that haven't been > > diagnosed or fixed yet. These issues prevent the system from actually > > suspending. So disable the driver in this case. Later, when this is > > fixed properly, we can remove this. > > How about just keeping it enabled, but not making it a fatal error if > the TPM saving doesn't work? IOW, just print the warning, and then > "return 0" from the suspend function. You're right that returning 0 from the pm notifier would make the problem that users actually care about -- laptop doesn't sleep when you close the lid -- go away. >From a random.c perspective, the RNG is already initialized when the driver loads, which will be before suspend bricks the driver. So even if the behavior afterwards is a buggy driver handing all zeros to random.c, it won't really matter much; random.c can deal with that cryptographically. I have no idea if this is actually the case with the driver's error condition. But if it is, it's good that it doesn't matter. So okay, I'll roll a patch to do that when I get home. I'm writing on my phone now, but from memory it's just changing a 'return rc;' into 'return 0;'. Then the TPM folks can fix the underlying issue at their leisure whenever. Jason
