Hi all, If NO_DMA=y, get_dma_ops() returns a reference to the non-existing symbol bad_dma_ops, thus causing a link failure if it is ever used. The intention of this is twofold: 1. To catch users of the DMA API on systems that do no support the DMA mapping API, 2. To avoid building drivers that cannot work on such systems anyway. However, the disadvantage is that we have to keep on adding dependencies on HAS_DMA all over the place. Thanks to the COMPILE_TEST symbol, lots of drivers now depend on one or more platform dependencies (that imply HAS_DMA) || COMPILE_TEST, thus already covering intention #2. Having to add an explicit dependency on HAS_DMA here is cumbersome, and hinders compile-testing. Hence I think the time is ripe to reconsider the link failure. Patch series "[PATCH v2 0/5] Allow compile-testing NO_DMA (core)" (https://lkml.org/lkml/2018/3/16/435) already: - Changed get_dma_ops() to return NULL instead, - Added a few more dummies to enable compile-testing. This patch series: - Removes dependencies on HAS_DMA for symbols that already have platform dependencies implying HAS_DMA. To avoid allmodconfig/allyesconfig regressions on NO_DMA=y platforms, this (drivers) series should be applied after the previous (core) series (but not many people may notice/care ;-) Changes compared to v1: - Add Reviewed-by, Acked-by, - Drop dependency of SND_SOC_LPASS_IPQ806X on HAS_DMA, - Drop dependency of VIDEOBUF{,2}_DMA_{CONTIG,SG} on HAS_DMA, - Drop new dependencies of VIDEO_IPU3_CIO2, DVB_C8SECTPFE, and MTD_NAND_MARVELL on HAS_DMA, - Split in per-subsystem patches, - Split-off the core part in a separate series. This series is against v4.16-rc5. It can also be found at https://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k.git/log/?h=no-dma-compile-testing-v2 It has been compile-tested with allmodconfig and allyesconfig for m68k/sun3, and has received attention from the kbuild test robot. Thanks! Geert Uytterhoeven (21): ASoC: Remove depends on HAS_DMA in case of platform dependency ata: Remove depends on HAS_DMA in case of platform dependency crypto: Remove depends on HAS_DMA in case of platform dependency fbdev: Remove depends on HAS_DMA in case of platform dependency firewire: Remove depends on HAS_DMA in case of platform dependency fpga: Remove depends on HAS_DMA in case of platform dependency i2c: Remove depends on HAS_DMA in case of platform dependency iio: adc: Remove depends on HAS_DMA in case of platform dependency iommu: Remove depends on HAS_DMA in case of platform dependency lightnvm: Remove depends on HAS_DMA in case of platform dependency mailbox: Remove depends on HAS_DMA in case of platform dependency media: Remove depends on HAS_DMA in case of platform dependency mmc: Remove depends on HAS_DMA in case of platform dependency mtd: Remove depends on HAS_DMA in case of platform dependency net: Remove depends on HAS_DMA in case of platform dependency remoteproc: Remove depends on HAS_DMA in case of platform dependency scsi: hisi_sas: Remove depends on HAS_DMA in case of platform dependency serial: Remove depends on HAS_DMA in case of platform dependency spi: Remove depends on HAS_DMA in case of platform dependency staging: vc04_services: Remove depends on HAS_DMA in case of platform dependency usb: Remove depends on HAS_DMA in case of platform dependency drivers/ata/Kconfig | 2 -- drivers/crypto/Kconfig | 14 +++------ drivers/firewire/Kconfig | 1 - drivers/fpga/Kconfig | 1 - drivers/i2c/busses/Kconfig | 3 -- drivers/iio/adc/Kconfig | 2 -- drivers/iommu/Kconfig | 5 ++-- drivers/lightnvm/Kconfig | 2 +- drivers/mailbox/Kconfig | 2 -- drivers/media/common/videobuf2/Kconfig | 2 -- drivers/media/pci/dt3155/Kconfig | 1 - drivers/media/pci/intel/ipu3/Kconfig | 1 - drivers/media/pci/solo6x10/Kconfig | 1 - drivers/media/pci/sta2x11/Kconfig | 1 - drivers/media/pci/tw5864/Kconfig | 1 - drivers/media/pci/tw686x/Kconfig | 1 - drivers/media/platform/Kconfig | 40 ++++++++----------------- drivers/media/platform/am437x/Kconfig | 2 +- drivers/media/platform/atmel/Kconfig | 4 +-- drivers/media/platform/blackfin/Kconfig | 1 - drivers/media/platform/davinci/Kconfig | 6 ---- drivers/media/platform/marvell-ccic/Kconfig | 3 +- drivers/media/platform/rcar-vin/Kconfig | 2 +- drivers/media/platform/soc_camera/Kconfig | 3 +- drivers/media/platform/sti/c8sectpfe/Kconfig | 2 +- drivers/media/v4l2-core/Kconfig | 2 -- drivers/mmc/host/Kconfig | 10 ++----- drivers/mtd/nand/Kconfig | 8 ++--- drivers/mtd/spi-nor/Kconfig | 2 +- drivers/net/ethernet/amd/Kconfig | 2 +- drivers/net/ethernet/apm/xgene-v2/Kconfig | 1 - drivers/net/ethernet/apm/xgene/Kconfig | 1 - drivers/net/ethernet/arc/Kconfig | 6 ++-- drivers/net/ethernet/broadcom/Kconfig | 2 -- drivers/net/ethernet/calxeda/Kconfig | 2 +- drivers/net/ethernet/hisilicon/Kconfig | 2 +- drivers/net/ethernet/marvell/Kconfig | 8 ++--- drivers/net/ethernet/mellanox/mlxsw/Kconfig | 2 +- drivers/net/ethernet/renesas/Kconfig | 2 -- drivers/net/wireless/broadcom/brcm80211/Kconfig | 1 - drivers/net/wireless/quantenna/qtnfmac/Kconfig | 2 +- drivers/remoteproc/Kconfig | 1 - drivers/scsi/hisi_sas/Kconfig | 2 +- drivers/spi/Kconfig | 12 ++------ drivers/staging/media/davinci_vpfe/Kconfig | 1 - drivers/staging/media/omap4iss/Kconfig | 1 - drivers/staging/vc04_services/Kconfig | 1 - drivers/tty/serial/Kconfig | 4 --- drivers/usb/gadget/udc/Kconfig | 4 +-- drivers/usb/mtu3/Kconfig | 2 +- drivers/video/fbdev/Kconfig | 3 +- sound/soc/bcm/Kconfig | 3 +- sound/soc/kirkwood/Kconfig | 1 - sound/soc/pxa/Kconfig | 1 - sound/soc/qcom/Kconfig | 7 ++--- 55 files changed, 56 insertions(+), 143 deletions(-) -- 2.7.4 Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html