-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 10/12/12 17:04, Garrett Cooper wrote: > On Fri, Oct 12, 2012 at 4:30 PM, Xin Li <delphij_at_delphij.net> > wrote: >> Hi, >> >> We have some rather hacky quick hack at $WORK that addresses a >> problem we have found with boot2/loader and wants to share it and >> see if we can have more neat solution. >> >> Here is the problem: the current boot2 and loader have various >> places where it considers serial port to exist. When the port is >> not there, the code would hang because it tests whether the >> hardware's -READY bit, basically something like: >> >> do { } while (inpb(state register) & READY_BIT); >> >> This unfortunately would enter an infinite loop when the device >> is not present -- all in operations would get all bits set. >> >> To reproduce this, one can compile boot2/loader with non-existent >> port and the system will hang at very early stage of boot. >> >> --- >> >> Because boot2 is size constrained we can not use very >> sophisticated detection logic there, what I did is to use >> something like: >> >> outb(line control register, word) if (inb(line control register) >> != word) Disable the serial port read/write >> >> For loader I'm not sure if we should use better detection logic. >> By the way, it seems that the system may force using the default >> console in loader regardless if the detection logic said no, if >> it decides that's the only usable one. >> >> So what would be the right way to solve these issue? > > Have you tried out Andriy's commit yet to loader(8) (r241301)? Ah I wish I am not this far behind my email backlog. Yes I think these (241300 and 241301) will solve the problem. Cheers, - -- Xin LI <delphij_at_delphij.net> https://www.delphij.net/ FreeBSD - The Power to Serve! Live free or die -----BEGIN PGP SIGNATURE----- iQEcBAEBCAAGBQJQeLFFAAoJEG80Jeu8UPuzktAH/3nyrSCrvHWlOSp/eOWf1oMU KQwzyUXOVgKWCVTHUYHN6tCs0sN1Vguc1n+Q8tqSCuDOJ4/x0lyb6GcyxZv2tf6+ gGYE54yYjf9UDM0HQ3Zb3ZxmH8Z06eH3jK/SlUg8nMXnReLW2v1KkuQ+T3yTyhQH 7vCjOzQylF4CmzpS7l/skNL2lxkJsoD/XROFzRrDAUSK2rdnupjUIxuTXI2G+Bjf i51qFZk6JRHnecL2c4Zm6ynO65eXyD0Ux7l+FOa00ntOKD33/HJP/Qtpl2UrU+J5 YhMcPUU2uRM3LTSl2D3mtbasrgKQMTmH4syp4ucR7belFPloX7RYjHItQdO6x1M= =0R8e -----END PGP SIGNATURE-----Received on Fri Oct 12 2012 - 22:09:42 UTC
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