>>>>> "marcel" == Marcel Pol <[EMAIL PROTECTED]> writes:
Hi marcel> While reading slashdot, I found this comment interesting (yes, that does marcel> happen on slashdot :-) ) marcel> http://slashdot.org/comments.pl?sid=83579&cid=7310813 marcel> "Why is Linux trying to send a flush cache command to a CD-ROM drive in the marcel> first place? That's a stupid thing to do. The ATAPI FLUSH CACHE command tells marcel> the device to flush its write cache to the media. A CD-ROM has no write cache, marcel> and can't write to any media. Of course, it's even more stupid for a drive to marcel> self-destruct when it gets a flush cache command..." marcel> Is this maybe 2 bugs "working together"? Using FLUSH_CACHE where it shouldn't, marcel> and have the cdrom reading that as UPLOAD_FIRMWARE Yes. there are two bugs here: - One, sending FLUSH_CACHE to a CD-ROM drive. CD-ROM drive decides: * do nothing (i.e. it don't have a cache, nothing to do). * return an error (Are you stupid, I don't have write capability). * return an "unimplemented/unknown command" Any of the three returns is ok. The reason of sending a FLUSH_CACHE for a CDROM is that way, we can share the CD-ROM and CD-RW code for packet writing. - Now the big problem: * ATAPI spec states that one CDROM not implementing FLUSH_CACHE command is ok, but using that command to do anything else is not allowed. - Problem 2: Having any kind of modify firmware command that don't test that the payload of the command is a firmware by checksum/signature/etc is just the more stupid thing that you can do in hardware world. Later, Juan. -- In theory, practice and theory are the same, but in practice they are different -- Larry McVoy
