RPI4 mmc device fails without WITNESS option ?

[Søren Schmidt]

Hi

Just wanted to check perf on a 4G RPI€ here, and without WITNESS in the kernel config it hangs:
CPU  1: ARM Cortex-A72 r0p3 affinity:  1
CPU  2: ARM Cortex-A72 r0p3 affinity:  2
CPU  3: ARM Cortex-A72 r0p3 affinity:  3
regulator: shutting down unused regulators
sdhci_bcm0-slot0: Controller timeout
sdhci_bcm0-slot0: ============== REGISTER DUMP ==============
sdhci_bcm0-slot0: Sys addr: 0x000000c8 | Version:  0x00001002
sdhci_bcm0-slot0: Blk size: 0x00000200 | Blk cnt:  0x00000004
sdhci_bcm0-slot0: Argument: 0x01cf7fc1 | Trn mode: 0x00000036
sdhci_bcm0-slot0: Present:  0x1fff0a06 | Host ctl: 0x00000007
sdhci_bcm0-slot0: Power:    0x0000000f | Blk gap:  0x00000080
sdhci_bcm0-slot0: Wake-up:  0x00000000 | Clock:    0x00000107
sdhci_bcm0-slot0: Timeout:  0x00000003 | Int stat: 0x00000000
sdhci_bcm0-slot0: Int enab: 0x01ff003b | Sig enab: 0x01ff0009
sdhci_bcm0-slot0: AC12 err: 0x00000000 | Host ctl2:0x00000000
sdhci_bcm0-slot0: Caps:     0x45ee6432 | Caps2:    0x0000a525
sdhci_bcm0-slot0: Max curr: 0x00080008 | ADMA err: 0x00000000
sdhci_bcm0-slot0: ADMA addr:0x00000000 | Slot int: 0x00000000
sdhci_bcm0-slot0: ===========================================
mmcsd0: Error indicated: 1 Timeout
mmcsd0: Error indicated: 1 Timeout
mmcsd0: Error indicated: 1 Timeout
mmcsd0: Error indicated: 1 Timeout
mmcsd0: Error indicated: 1 Timeout
mountroot: waiting for device /dev/mmcsd0s2a...
Mounting from ufs:/dev/mmcsd0s2a failed with error 19.

With WITNESS enabled it just chuck along and boots..

Ideas ?

-Søren