On 3/13/22 1:15 PM, Ondrej Zary wrote: > On Saturday 12 March 2022 15:44:15 Ondrej Zary wrote: >> The pata_parport is a libata-based replacement of the old PARIDE >> subsystem - driver for parallel port IDE devices. >> It uses the original paride low-level protocol drivers but does not >> need the high-level drivers (pd, pcd, pf, pt, pg). The IDE devices >> behind parallel port adapters are handled by the ATA layer. >> >> This will allow paride and its high-level drivers to be removed. >> >> paride and pata_parport are mutually exclusive because the compiled >> protocol drivers are incompatible. >> >> Tested with Imation SuperDisk LS-120 and HP C4381A (both use EPAT >> chip). >> >> Note: EPP-32 mode is buggy in EPAT - and also in all other protocol >> drivers - they don't handle non-multiple-of-4 block transfers >> correctly. This causes problems with LS-120 drive. >> There is also another bug in EPAT: EPP modes don't work unless a 4-bit >> or 8-bit mode is used first (probably some initialization missing?). >> Once the device is initialized, EPP works until power cycle. >> >> So after device power on, you have to: >> echo "parport0 epat 0" >/sys/bus/pata_parport/new_device >> echo pata_parport.0 >/sys/bus/pata_parport/delete_device >> echo "parport0 epat 4" >/sys/bus/pata_parport/new_device >> (autoprobe will initialize correctly as it tries the slowest modes >> first but you'll get the broken EPP-32 mode) > > Found a bug - the same device can be registered multiple times. Fix > will be in v2. But this revealed a bigger problem: pi_connect can > sleep (uses parport_claim_or_block) and libata does not like that. Any > ideas how to fix this? I think you'd need two things here: - The blk-mq queue should be registered with BLK_MQ_F_BLOCKING, which will allow blocking off the queue_rq path. - You need to look at making libata safe wrt calling ata_qc_issue() outside the lock. Should probably be fine if you just gate that on whether or not the queue was setup in blocking mode, as that doesn't currently exist in libata. -- Jens Axboe
