[Bug 2167177] [NEW] Intermittent SPI keyboard/trackpad failure at boot — DMA/PIO module load order race in spi_pxa2xx_pci

Public bug reported: On a MacBook8,1 (2016 12" MacBook, Intel Broadwell), the internal SPI keyboard and trackpad intermittently fail to initialize at boot. A restart always resolves the issue. The failure is caused by a race between dw_dmac_pci and pxa2xx_spi_pci module probe order. Symptoms: Intermittent: keyboard and trackpad not detected after boot (no input: Apple SPI Keyboard / input: Apple SPI Touchpad in dmesg) Restart always fixes it No external keyboard required to reproduce (it's a boot-time race) Root Cause: The spi_pxa2xx_pci driver checks for DMA channel availability at probe time. The outcome depends on whether dw_dmac_pci has already registered its channels: Good boot: pxa2xx_spi_pci probes first → "no DMA channels available, using PIO" → works Bad boot: dw_dmac_pci probes first → SPI sees DMA → uses DMA → transfers time out (-110) → driver re-queues a message still linked in the SPI core's list → list corruption (__list_add_valid_or_report warning) → driver is permanently stuck Failed boot log (kernel 7.0.0-31-generic): dw_dmac_pci 0000:00:15.0: DesignWare DMA Controller, 8 channels input: Apple SPI Keyboard as /devices/pci0000:00/0000:00:15.4/spi_master/spi1/spi-APP000D:00/input/input4 applespi spi-APP000D:00: SPI transfer timed out applespi spi-APP000D:00: Error writing to device: -110 spi_master spi1: failed to transfer one message from queue applespi spi-APP000D:00: SPI transfer timed out applespi spi-APP000D:00: Error reading from device: -110 WARNING: lib/list_debug.c:35 at __list_add_valid_or_report+0xc6/0xe0, CPU#3: spi1/455 spi_queued_transfer+0xed/0x110 __spi_async+0xd5/0x160 spi_async+0xd6/0xe0 applespi_send_cmd_msg+0x17d/0x400 [applespi] applespi_msg_complete+0xc5/0x110 [applespi] applespi_async_read_complete+0x5c/0x60 [applespi] spi_master spi1: failed to transfer one message from queue applespi spi-APP000D:00: SPI transfer timed out applespi spi-APP000D:00: Error writing to device: -110 Successful boot log (same kernel, same machine): pxa2xx_spi_pci 0000:00:15.4: no DMA channels available, using PIO dw_dmac_pci 0000:00:15.0: DesignWare DMA Controller, 8 channels input: Apple SPI Keyboard as /devices/pci0000:00/0000:00:15.4/spi_master/spi1/spi-APP000D:00/input/input4 applespi spi-APP000D:00: Received corrupted packet (crc mismatch) applespi spi-APP000D:00: modeswitch done. input: Apple SPI Touchpad as /devices/pci0000:00/0000:00:15.4/spi_master/spi1/spi-APP000D:00/input/input5 Upstream Status: The list-corruption bug (re-queueing applespi->wr_m via spi_async() while still linked in SPI core lists) was identified in the sashiko-bot review of the v4/v5 patch series (Shih-Yuan Lee, July 2026, linux-spi mailing list). The same series adds a force_pio module parameter to spi_pxa2xx_pci as a workaround. Workaround (untested, for reference): # /etc/modprobe.d/spi-force-pio.conf options spi_pxa2xx_pci force_pio=1 (Requires the upstream patch to be applied; the parameter does not exist in 7.0.0-31-generic.) System: Ubuntu 24.04.1 LTS Kernel: 7.0.0-31-generic Hardware: MacBook8,1 (Intel Core M, Broadwell) SPI controller: Intel LPSS at 00:15.4 DMA controller: DesignWare at 00:15.0 ** Affects: linux (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb https://bugs.launchpad.net/bugs/2167177 Title: Intermittent SPI keyboard/trackpad failure at boot — DMA/PIO module load order race in spi_pxa2xx_pci Status in linux package in Ubuntu: New Bug description: On a MacBook8,1 (2016 12" MacBook, Intel Broadwell), the internal SPI keyboard and trackpad intermittently fail to initialize at boot. A restart always resolves the issue. The failure is caused by a race between dw_dmac_pci and pxa2xx_spi_pci module probe order. Symptoms: Intermittent: keyboard and trackpad not detected after boot (no input: Apple SPI Keyboard / input: Apple SPI Touchpad in dmesg) Restart always fixes it No external keyboard required to reproduce (it's a boot-time race) Root Cause: The spi_pxa2xx_pci driver checks for DMA channel availability at probe time. The outcome depends on whether dw_dmac_pci has already registered its channels: Good boot: pxa2xx_spi_pci probes first → "no DMA channels available, using PIO" → works Bad boot: dw_dmac_pci probes first → SPI sees DMA → uses DMA → transfers time out (-110) → driver re-queues a message still linked in the SPI core's list → list corruption (__list_add_valid_or_report warning) → driver is permanently stuck Failed boot log (kernel 7.0.0-31-generic): dw_dmac_pci 0000:00:15.0: DesignWare DMA Controller, 8 channels input: Apple SPI Keyboard as /devices/pci0000:00/0000:00:15.4/spi_master/spi1/spi-APP000D:00/input/input4 applespi spi-APP000D:00: SPI transfer timed out applespi spi-APP000D:00: Error writing to device: -110 spi_master spi1: failed to transfer one message from queue applespi spi-APP000D:00: SPI transfer timed out applespi spi-APP000D:00: Error reading from device: -110 WARNING: lib/list_debug.c:35 at __list_add_valid_or_report+0xc6/0xe0, CPU#3: spi1/455 spi_queued_transfer+0xed/0x110 __spi_async+0xd5/0x160 spi_async+0xd6/0xe0 applespi_send_cmd_msg+0x17d/0x400 [applespi] applespi_msg_complete+0xc5/0x110 [applespi] applespi_async_read_complete+0x5c/0x60 [applespi] spi_master spi1: failed to transfer one message from queue applespi spi-APP000D:00: SPI transfer timed out applespi spi-APP000D:00: Error writing to device: -110 Successful boot log (same kernel, same machine): pxa2xx_spi_pci 0000:00:15.4: no DMA channels available, using PIO dw_dmac_pci 0000:00:15.0: DesignWare DMA Controller, 8 channels input: Apple SPI Keyboard as /devices/pci0000:00/0000:00:15.4/spi_master/spi1/spi-APP000D:00/input/input4 applespi spi-APP000D:00: Received corrupted packet (crc mismatch) applespi spi-APP000D:00: modeswitch done. input: Apple SPI Touchpad as /devices/pci0000:00/0000:00:15.4/spi_master/spi1/spi-APP000D:00/input/input5 Upstream Status: The list-corruption bug (re-queueing applespi->wr_m via spi_async() while still linked in SPI core lists) was identified in the sashiko- bot review of the v4/v5 patch series (Shih-Yuan Lee, July 2026, linux- spi mailing list). The same series adds a force_pio module parameter to spi_pxa2xx_pci as a workaround. Workaround (untested, for reference): # /etc/modprobe.d/spi-force-pio.conf options spi_pxa2xx_pci force_pio=1 (Requires the upstream patch to be applied; the parameter does not exist in 7.0.0-31-generic.) System: Ubuntu 24.04.1 LTS Kernel: 7.0.0-31-generic Hardware: MacBook8,1 (Intel Core M, Broadwell) SPI controller: Intel LPSS at 00:15.4 DMA controller: DesignWare at 00:15.0 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2167177/+subscriptions