Messages in this thread | | | Date | Thu, 18 May 2006 20:33:23 +0900 | From | Tejun Heo <> | Subject | Re: [RFT] major libata update |
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Albert Lee wrote: >> To sum up, it happens when the master slot is occupied by an ATAPI >> device and the corresponding slave slot is empty. The slave slot >> reports ATAPI signature (probably duplicated from the master) and passes >> all legacy presence test thus resulting in timeout on IDENTIFY. >> > > This problem was seen with PATA Promise 20275 adapter + IBM DVD-RAM drive. > Single master device configuration, no slave device. > The master device acts as slave and creates a phantom slave device. > (http://marc.theaimsgroup.com/?l=linux-ide&m=113151315602979&w=2) > > The problem was later fixed by Tejun's ata_exec_internal() patch: > (http://marc.theaimsgroup.com/?l=linux-ide&m=113455450809405&w=2) > After the patch, the phantom device is finally detected by ata_dev_identify(). > > Libata uses polling PIO for IDENTIFY DEVICE before this major update. > The polling PIO finds something wrong when it reads a 0x00 device status. > So, the phantom device is detected quite quickly. > > With irq-driven PIO, maybe the phantom device is only detected after time-out. > So it takes longer (30 secs) to detect the phantom device. > > No good idea how to fix this. Maybe read more registers to see whether the > phantom device can be detected early before the IDENTIFY DEVICE. >
Does the Promise controller show the ghosting problem again with the recent updates? ata_piix can be fixed by using PCS present bits. I don't know about Promise though.
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