In-Reply-To: <20210527124356.22367-1-will@xxxxxxxxxx> > Reduce ARCH_DMA_MINALIGN to 64 bytes and allow the warning/taint to > indicate if there are machines that unknowingly rely on this. The warning is being triggered on Qualcomm MSM8996, as well as the out-of-spec taint: ------------[ cut here ]------------ rtc-pm8xxx 400f000.qcom,spmi:pmic@0:rtc@6000: ARCH_DMA_MINALIGN smaller than CTR_EL0.CWG (64 < 128) WARNING: CPU: 0 PID: 1 at arch/arm64/mm/dma-mapping.c:45 arch_setup_dma_ops+0xf8/0x10c Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Tainted: G S 5.13.0+ #43 Hardware name: Xiaomi Mi Note 2 (DT) pstate: 60000005 (nZCv daif -PAN -UAO -TCO BTYPE=--) pc : arch_setup_dma_ops+0xf8/0x10c lr : arch_setup_dma_ops+0xf8/0x10c sp : ffff80001003bb50 x29: ffff80001003bb50 x28: 0000000000000000 x27: ffff800010ee04c0 x26: ffff800010f41060 x25: 00000000ffffffff x24: 0000000000000000 x23: 0000000000000080 x22: 0000000000000000 x21: 0000000000000000 x20: 0000000100000000 x19: ffff00008143e010 x18: ffffffffffffffff x17: 696c206f74205d72 x16: 656874655f675b20 x15: ffff800011212d34 x14: 0000000000000000 x13: ffff8000110d4620 x12: 0000000000001047 x11: 000000000000056d x10: ffff8000110d4620 x9 : ffff8000110d4620 x8 : 00000000ffffefff x7 : ffff80001112c620 x6 : ffff80001112c620 x5 : 0000000000000000 x4 : 0000000000000000 x3 : 00000000ffffffff x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000080098000 Call trace: arch_setup_dma_ops+0xf8/0x10c of_dma_configure_id+0x120/0x2a4 platform_dma_configure+0x24/0x40 really_probe.part.0+0x50/0x2fc __driver_probe_device+0x98/0x144 driver_probe_device+0xc8/0x15c __driver_attach+0xf8/0x190 bus_for_each_dev+0x70/0xd0 driver_attach+0x24/0x30 bus_add_driver+0x104/0x1ec driver_register+0x78/0x130 __platform_driver_register+0x28/0x34 pm8xxx_rtc_driver_init+0x1c/0x28 do_one_initcall+0x50/0x1b0 kernel_init_freeable+0x214/0x298 kernel_init+0x28/0x12c ret_from_fork+0x10/0x18 ---[ end trace 09b7616a3af9b190 ]--- This warning is triggered with nearly every driver probe, not only rtc-pm8xxx.
