Christoph Muellner a3eec13b8f arm64: dts: rockchip: Disable DCMDs on RK3399's eMMC controller. ... When using direct commands (DCMDs) on an RK3399, we get spurious CQE completion interrupts for the DCMD transaction slot (#31): [ 931.196520] ------------[ cut here ]------------ [ 931.201702] mmc1: cqhci: spurious TCN for tag 31 [ 931.206906] WARNING: CPU: 0 PID: 1433 at /usr/src/kernel/drivers/mmc/host/cqhci.c:725 cqhci_irq+0x2e4/0x490 [ 931.206909] Modules linked in: [ 931.206918] CPU: 0 PID: 1433 Comm: irq/29-mmc1 Not tainted 4.19.8-rt6-funkadelic #1 [ 931.206920] Hardware name: Theobroma Systems RK3399-Q7 SoM (DT) [ 931.206924] pstate: 40000005 (nZcv daif -PAN -UAO) [ 931.206927] pc : cqhci_irq+0x2e4/0x490 [ 931.206931] lr : cqhci_irq+0x2e4/0x490 [ 931.206933] sp : ffff00000e54bc80 [ 931.206934] x29: ffff00000e54bc80 x28: 0000000000000000 [ 931.206939] x27: 0000000000000001 x26: ffff000008f217e8 [ 931.206944] x25: ffff8000f02ef030 x24: ffff0000091417b0 [ 931.206948] x23: ffff0000090aa000 x22: ffff8000f008b000 [ 931.206953] x21: 0000000000000002 x20: 000000000000001f [ 931.206957] x19: ffff8000f02ef018 x18: ffffffffffffffff [ 931.206961] x17: 0000000000000000 x16: 0000000000000000 [ 931.206966] x15: ffff0000090aa6c8 x14: 0720072007200720 [ 931.206970] x13: 0720072007200720 x12: 0720072007200720 [ 931.206975] x11: 0720072007200720 x10: 0720072007200720 [ 931.206980] x9 : 0720072007200720 x8 : 0720072007200720 [ 931.206984] x7 : 0720073107330720 x6 : 00000000000005a0 [ 931.206988] x5 : ffff00000860d4b0 x4 : 0000000000000000 [ 931.206993] x3 : 0000000000000001 x2 : 0000000000000001 [ 931.206997] x1 : 1bde3a91b0d4d900 x0 : 0000000000000000 [ 931.207001] Call trace: [ 931.207005] cqhci_irq+0x2e4/0x490 [ 931.207009] sdhci_arasan_cqhci_irq+0x5c/0x90 [ 931.207013] sdhci_irq+0x98/0x930 [ 931.207019] irq_forced_thread_fn+0x2c/0xa0 [ 931.207023] irq_thread+0x114/0x1c0 [ 931.207027] kthread+0x128/0x130 [ 931.207032] ret_from_fork+0x10/0x20 [ 931.207035] ---[ end trace 0000000000000002 ]--- The driver shows this message only for the first spurious interrupt by using WARN_ONCE(). Changing this to WARN() shows, that this is happening quite frequently (up to once a second). Since the eMMC 5.1 specification, where CQE and CQHCI are specified, does not mention that spurious TCN interrupts for DCMDs can be simply ignored, we must assume that using this feature is not working reliably. The current implementation uses DCMD for REQ_OP_FLUSH only, and I could not see any performance/power impact when disabling this optional feature for RK3399. Therefore this patch disables DCMDs for RK3399. Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com> Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com> Fixes: 84362d79f4 ("mmc: sdhci-of-arasan: Add CQHCI support for arasan,sdhci-5.1") Cc: stable@vger.kernel.org [the corresponding code changes are queued for 5.2 so doing that as well] Signed-off-by: Heiko Stuebner <heiko@sntech.de>		2019-03-27 13:18:22 +01:00
..
boot	arm64: dts: rockchip: Disable DCMDs on RK3399's eMMC controller.	2019-03-27 13:18:22 +01:00
configs	Allwinner arm64 defconfig changes for 5.1	2019-02-15 16:51:26 +01:00
crypto	Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6	2019-03-05 09:09:55 -08:00
include	Kbuild updates for v5.1 (2nd)	2019-03-17 13:25:26 -07:00
kernel	treewide: add checks for the return value of memblock_alloc*()	2019-03-12 10:04:02 -07:00
kvm	ARM: some cleanups, direct physical timer assignment, cache sanitization	2019-03-15 15:00:28 -07:00
lib	arm64: string: use asm EXPORT_SYMBOL()	2018-12-10 11:50:12 +00:00
mm	treewide: add checks for the return value of memblock_alloc*()	2019-03-12 10:04:02 -07:00
net	arm64: bpf: implement jitting of JMP32	2019-01-26 13:33:02 -08:00
xen	arm64: mm: Add additional parameter to uaccess_ttbr0_disable	2018-01-17 13:57:49 +01:00
Kconfig	DMA mapping updates for 5.1	2019-03-10 11:54:48 -07:00
Kconfig.debug	Kconfig: consolidate the "Kernel hacking" menu	2018-08-02 08:06:48 +09:00
Kconfig.platforms	arm64 updates for 5.1:	2019-03-10 10:17:23 -07:00
Makefile	kasan, arm64: adjust shadow size for tag-based mode	2018-12-28 12:11:43 -08:00