This is a well-established ticket with a working (unsupported) patch for Fedora Core 4. I could not find a similar ticket for RHEL4. From linked Bugzilla report: "Various thinkpads with SATA controllers (actually, they have PATA hard drives with PATA to SATA adapters, aparently) cannot recover from suspend to RAM due to lack of power management support in SATA."
I'm having this problem with an IBM Thinkpad T43 and RHEL 4 U4 (2.6.9-42). Machine suspends to RAM, but when waking stops responding with the kind of console messages described in BZ#169201: kernel: journal commit I/O error end_request: I/O error, dev sda, sector 121135224 sd 0:0:0:0: SCSI error return code: 0x4000 etc. Any news on this issue?
I don't have a platform to verify, but it looks like all the PM hooks exist in RHEL4 U8, closing this BZ, please re-open if necessary.