On Tue, Jun 07, 2022 at 07:29:03AM +0000, bugzilla-daemon@xxxxxxxxxx wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=216094 > > Summary: pci-mvebu: SATA HDDs via 88SE6121 AHCI fail with > Marvell 88F6281 PCIe > Kernel Version: 3.16 ... 5.10 > Reporter: hajo-linux-bugzilla@xxxxxxxxxxxxx > CC: pali@xxxxxxxxxx > Regression: No > > I would like to continue the SATA-related topic started with Pali > Rohár at the U-Boot mailing list [1]. I have analysed the issue > further and come the following conclusion that it is related to the > PCIe subsystem: > > SATA-2 and SATA-3 hard disks connected to a 88SE6121 (AHCI) > controller, wired via PCIe to the 88F6281 SoC fail to operate > ("failed to IDENTIFY" ... "qc timeout") when the pci-mvebu driver > (Kernel 3.16 .. 5.10 Debian) is in use. Please attach the complete dmesg logs showing this issue. >From your lspci output with v3.2, the SATA controller is at 00:01.0: 00:01.0 IDE [0101]: Marvell 88SE6121 SATA II The v3.16 (with DTB) lspci output is essentially the same except the controller is at 01:00.0: 01:00.0 IDE [0101]: Marvell 88SE6121 SATA II The ahci driver is bound in both cases. The PCI address and I/O port assignment differences are of no consequence unless some mvebu driver defect keeps them from working. I think what we need is a complete dmesg log and DTB from the newest possible kernel that fails, plus the same logs from the newest kernel that works. > More details: > > - The problem does not exist in 2.6 and 3.16 kernels. With the old > mach-kirkwood/pcie.c driver all SATA-2/3 hard disks work correctly. > Especially with a 3.16 kernel it is possible to have identical > ATA/AHCI drivers but try both PCIe drivers: without DTB -> > mach-kirkwood -> SATA-2/3 HDDs work; with DTB -> mach-mvebu -> HDDs > fail. > > - The problem is specific to SATA-2/3 HDDs. Very old SATA-1-only > HDDs work without problems. This might be related to the available > data lanes, DMA or other bandwidth-related things -- I can only > guess. Interestingly it does not help to limit SATA speed > (libata.force=1.5G ...) with SATA-2/3 HDDs, only 'pure' SATA-1 HDDs > work with pci-mvebu. > > - The problem was identified with the Seagate Blackarmor NAS440 > hardware. Forum posts show that other users experience similar > problems with the (very similar) Iomega ix4-200d NAS [2]. > > - Within patched U-Boot [3] all (Sata-1/2/3) HDDs always work. Same > for the 88F6281 SoC onboard SATA ports (sata_mv - not connected via > PCIe). > > - The mach-kirkwood driver operates the 6281 as class "Host bridge > [0600]" with Cap "Express (v1) Root Port", the mach-mvebu driver as > class "PCI bridge [0604]" with "Express (v2) Root Port" > [4][5][6][7]. Notably the v1/v2, cache line size 32/64 or the > missing interrupt route might be a key difference. > > From the sources I see that all PCI drivers (mach-kirkwood, > mach-mvebu and U-Boot) do various unconventional 'magic' things > (rewriting PCI class of the root complex, changing capabilitys, host > emulation and so on). This is the point where I currently get lost > and ask for your help. > [1] https://lists.denx.de/pipermail/u-boot/2022-March/479197.html > [2] https://forum.doozan.com/read.php?2,94079,95519#msg-95519 > [3] https://lists.denx.de/pipermail/u-boot/2022-March/479227.html > [4] lspci Linux version 3.2.0-4-kirkwood mach-kirkwood/pci.c: HDDs ok > [5] lspci Linux version 3.16.0-0.bpo.4-kirkwood - with DTB -> mvebu-pci: HDDs > fail > [6] lspci Linux version 3.16.0-0.bpo.4-kirkwood - without DTB -> > mach-kirkwood/pci.c: HDDs ok > [7] lspci Linux version 5.10.0-11-marvell (Debian bullseye) mvebu-pci: HDDs > fail
