From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 15 Jan 1998 08:50:15 -0500 From: Mark Salyzyn mark@bohica.dpt.com Subject: [9fans] Re: DPT PM2041W observations Topicbox-Message-UUID: 702694f4-eac8-11e9-9e20-41e7f4b1d025 Message-ID: <19980115135015.AedYSG8SZ1RmeRYUaSXU50fi-47Szx7EyB3TEKns3J8@z> gdb@dbsystems.COM (G. David Butler) writes: > How do I abort a command? place the same physical address of the CCB into the mailbox registers ([base+2]=MSb -> [base+5]=Lsb) as you would do when sending the command. Place 0x03 (Abort immediate command) into [base+6] and send the EATA immediate command (0xFA) into [base+7]. The command will cause the eventual acknowledgement interrupt indicating the completion status (recognizing that it may be a Host adapter ABORT, a SCSI bus ABORT, or completed successfully). > If a driver needs to time out on a command and reclaim the > memory, how do I tell the DPT that not only am I not interested > in command anymore, but if it returns with the address of > a ccb the driver has reused, bad things will happen. The DPT controller will *always* return a matching interrupt for all commands issued. Not waiting for that matching interrupt would be `vary bad'. Some operating systems have SCSI midlevel code that understands sending an abort, some just send a SCSI Bus Reset and wait for all the commands to return, indicating that they were terminated by a SCSI Bus reset. This 1:1 matching of the commands to interrupts is quaranteed, no lost commands! > If there is a way to abort the command to the adapter, > how long does it wait for the queued command to come back > from the target? What happens if that is not long enough? > Or does the adapter tell the target to abort the queued > operation? The adapter, for DASD devices, will retry the command every 10 seconds automagically. For all other devices, it waits patiently (unless a SCSI Bus reset, device reset, or an abort message is created). > Is there a current technical reference manual? Yes. A simple NDA will fill your disk with lots of WORD documents! If interested, contact Tom Childers to make arrangements. Sincerely -- Mark Salyzyn