Chris's caroline got slow, and at the next suspend/resume cycle showed a black screen for about 20s after resume, then showed the lock screen but was totally unresponsive.

I did a triple alt-VolUpKey-X and then we sent this feedback report:

https://feedback.corp.google.com/#/Report/59811678283

The console-ramoops has lots of these, which seem to happen exactly every 10s:

[22479.883021] mmc0: Timeout waiting for hardware interrupt.
[22479.883056] sdhci: =========== REGISTER DUMP (mmc0)===========
[22479.883094] sdhci: Sys addr: 0x00000010 | Version:  0x00001002
[22479.883129] sdhci: Blk size: 0x00007200 | Blk cnt:  0x00000010
[22479.883164] sdhci: Argument: 0x00000000 | Trn mode: 0x00000023
[22479.883199] sdhci: Present:  0x1fff0000 | Host ctl: 0x00000019
[22479.883234] sdhci: Power:    0x0000000b | Blk gap:  0x00000080
[22479.883268] sdhci: Wake-up:  0x00000000 | Clock:    0x0000fa07
[22479.883302] sdhci: Timeout:  0x0000000e | Int stat: 0x00000000
[22479.883336] sdhci: Int enab: 0x02000008 | Sig enab: 0x02000008
[22479.883371] sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000
[22479.883405] sdhci: Caps:     0x546ec881 | Caps_1:   0x80000807
[22479.883440] sdhci: Cmd:      0x00000c1b | Max curr: 0x00000000
[22479.883472] sdhci: Host ctl2: 0x00000000
[22479.883503] sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x0000000001402000
[22479.883527] sdhci: ===========================================
[22489.898997] mmc0: Timeout waiting for hardware interrupt.
[22489.899026] sdhci: =========== REGISTER DUMP (mmc0)===========
[22489.899059] sdhci: Sys addr: 0x00000010 | Version:  0x00001002
[22489.899090] sdhci: Blk size: 0x00007200 | Blk cnt:  0x00000010
[22489.899121] sdhci: Argument: 0x00010000 | Trn mode: 0x00000023
[22489.899151] sdhci: Present:  0x1fff0000 | Host ctl: 0x00000019
[22489.899181] sdhci: Power:    0x0000000b | Blk gap:  0x00000080
[22489.899211] sdhci: Wake-up:  0x00000000 | Clock:    0x0000fa07
[22489.899242] sdhci: Timeout:  0x0000000e | Int stat: 0x00000000
[22489.899272] sdhci: Int enab: 0x02000008 | Sig enab: 0x02000008
[22489.899303] sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000
[22489.899333] sdhci: Caps:     0x546ec881 | Caps_1:   0x80000807
[22489.899363] sdhci: Cmd:      0x00000d1a | Max curr: 0x00000000
[22489.899391] sdhci: Host ctl2: 0x00000000
[22489.899419] sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x0000000001402000
[22489.899439] sdhci: ===========================================
[22489.901667] mmcblk0: error -110 sending status command, retrying
[22499.915000] mmc0: Timeout waiting for hardware interrupt.

Almost all of the stacks in the ramoops, possibly all of them, show threads blocked in file system operations.

I've searched bugs for "Timeout waiting for hardware interrupt" and found this one, which unfortunately doesn't have much information.

https://bugs.chromium.org/p/chromium/issues/detail?id=644818