On Wed, 31 Mar 2021, Christoph Hellwig wrote: > The ISA support in Buslogic has been broken for a long time, as all > the I/O path expects a struct device for DMA mapping that is derived from > the PCI device, which would simply crash for ISA adapters. With my new server in place I can experiment more with the old one, so I have decided to upgrade it from venerable 2.6.18 and give your change a try with the BT-958 to verify it does not cause a regression, but there is something wrong even without it: pci 0000:00:13.0: PCI->APIC IRQ transform: INT A -> IRQ 17 scsi: ***** BusLogic SCSI Driver Version 2.1.17 of 12 September 2013 ***** scsi: Copyright 1995-1998 by Leonard N. Zubkoff <lnz@xxxxxxxxxxxxx> scsi0: Configuring BusLogic Model BT-958 PCI Wide Ultra SCSI Host Adapter scsi0: Firmware Version: 5.07B, I/O Address: 0x7000, IRQ Channel: 17/Level scsi0: PCI Bus: 0, Device: 19, Address: 0xE0012000, Host Adapter SCSI ID: 7 scsi0: Parity Checking: Enabled, Extended Translation: Enabled scsi0: Synchronous Negotiation: Ultra, Wide Negotiation: Enabled scsi0: Disconnect/Reconnect: Enabled, Tagged Queuing: Enabled scsi0: Scatter/Gather Limit: 128 of 8192 segments, Mailboxes: 211 scsi0: Driver Queue Depth: 211, Host Adapter Queue Depth: 192 scsi0: Tagged Queue Depth: Automatic , Untagged Queue Depth: 3 scsi0: SCSI Bus Termination: Both Enabled , SCAM: Disabled scsi0: *** BusLogic BT-958 Initialized Successfully *** scsi host0: BusLogic BT-958 scsi 0:0:0:0: Direct-Access IBM DDYS-T18350M SA5A PQ: 0 ANSI: 3 scsi 0:0:1:0: Direct-Access SEAGATE ST336607LW 0006 PQ: 0 ANSI: 3 scsi 0:0:5:0: Direct-Access IOMEGA ZIP 100 E.08 PQ: 0 ANSI: 2 st: Version 20160209, fixed bufsize 32768, s/g segs 256 sd 0:0:0:0: [sda] 35843670 512-byte logical blocks: (18.4 GB/17.1 GiB) sd 0:0:1:0: [sdb] 71687372 512-byte logical blocks: (36.7 GB/34.2 GiB) sd 0:0:0:0: [sda] Write Protect is off sd 0:0:5:0: [sdc] Attached SCSI removable disk sd 0:0:1:0: [sdb] Write Protect is off sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA sd 0:0:1:0: [sdb] Write cache: enabled, read cache: enabled, supports DPO and FUA scsi0: *** BusLogic BT-958 Initialized Successfully *** scsi0: *** BusLogic BT-958 Initialized Successfully *** scsi0: *** BusLogic BT-958 Initialized Successfully *** scsi0: *** BusLogic BT-958 Initialized Successfully *** sd 0:0:0:0: Device offlined - not ready after error recovery sd 0:0:1:0: Device offlined - not ready after error recovery sd 0:0:1:0: [sdb] Attached SCSI disk sd 0:0:0:0: [sda] Attached SCSI disk sd 0:0:0:0: Attached scsi generic sg0 type 0 sd 0:0:1:0: Attached scsi generic sg1 type 0 sd 0:0:5:0: Attached scsi generic sg2 type 0 and obviously the system does not complete booting (root is on /dev/sda2). I'll see if I can bisect the problem and report back. I don't have a FlashPoint adapter to verify that part of the driver, but I guess for your change alone a MultiMaster one such as mine will suffice. Also `pr_cont' has not been applied here when `printk' handling was reworked causing messy output, so I'll fix it too on this occasion. Last but not least I do hope you do not plan to retire ISA DMA bounce buffering support for drivers/block/floppy.c, as there is hardly an alternative available (I do have a single SCSI<->FDD interface built around an Intel 8080 CPU, in the half-height 5.25" drive form factor, but such devices are exceedingly rare, and then you need a suitable parallel SCSI host too). Would it be feasible to convert it and any other drivers for ISA DMA devices (like those support for which you propose to remove here) still have users who could verify operation to the IOMMU framework? Maciej
