driver for apple storage controller 106b:2001

[Julien Grossholtz]

Hello everyone,

The issue is the same on some 2015 Macbook air. Not all of them, only those who are claiming to have an 
NVMExpress controler under OSX.  

Matthew Wilcox kindly answered to me a few month ago about this issue but I had the same behaviour than 
David's Macbook with the huge device page size.

Since then I spoke on some forums. With the 3.16 kernel someone had a different behaviour, he had some delay 
after the echo "106b 2001" > /sys/bus/pci/drivers/nvme/new_id
I'm not sure it is really usefull but anyway here is it's dmesg output :

$ echo "106b 2001" | sudo tee /sys/bus/pci/drivers/nvme/new_id
106b 2001
$ dmesg
[  136.279863] irq 16: nobody cared (try booting with the "irqpoll" option)
[  136.279872] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 3.16.0-30-generic #40~14.04.1-Ubuntu
[  136.279875] Hardware name: Apple Inc. MacBook8,1/Mac-BE0E8AC46FE800CC, BIOS MB81.88Z.0164.B02.1503241252 
03/24/2015
[  136.279877]  ffff880262992ca4 ffff88026ec83e58 ffffffff81762590 ffff880262992c00
[  136.279882]  ffff88026ec83e80 ffffffff810cd672 ffff880262992c00 0000000000000010
[  136.279886]  0000000000000000 ffff88026ec83ec0 ffffffff810cdbac 0000000000000000
[  136.279890] Call Trace:
[  136.279893]  <IRQ>  [<ffffffff81762590>] dump_stack+0x45/0x56
[  136.279906]  [<ffffffff810cd672>] __report_bad_irq+0x32/0xd0
[  136.279910]  [<ffffffff810cdbac>] note_interrupt+0x24c/0x2a0
[  136.279914]  [<ffffffff810cb29e>] handle_irq_event_percpu+0xae/0x1a0
[  136.279917]  [<ffffffff810cb3cd>] handle_irq_event+0x3d/0x60
[  136.279921]  [<ffffffff810ce771>] handle_fasteoi_irq+0x81/0x150
[  136.279927]  [<ffffffff810155ee>] handle_irq+0x1e/0x30
[  136.279931]  [<ffffffff8176dabf>] do_IRQ+0x4f/0xf0
[  136.279936]  [<ffffffff8176b96d>] common_interrupt+0x6d/0x6d
[  136.279937]  <EOI>  [<ffffffff815fb8a2>] ? cpuidle_enter_state+0x52/0xc0
[  136.279947]  [<ffffffff815fb898>] ? cpuidle_enter_state+0x48/0xc0
[  136.279952]  [<ffffffff815fb9c7>] cpuidle_enter+0x17/0x20
[  136.279957]  [<ffffffff810b528d>] cpu_startup_entry+0x31d/0x450
[  136.279961]  [<ffffffff8104526d>] start_secondary+0x21d/0x2e0
[  136.279963] handlers:
[  136.279969] [<ffffffffc048b5f0>] nvme_irq [nvme]
[  136.279972] Disabling IRQ #16
[  195.662642] nvme: probe of 0000:03:00.0 failed with error -4


This only means there was no handler for an interrupt right ? Is it an interrupt your are usually taking care 
of on Intel CPUs regarding NVNE ? 

I also discussed with a guy that is running windows on his Macbook. The Windows driver is only displayed as a 
"APPLE SSD AP0512 SCSI Disk Device" (I have some screenshots to share if needed). So maybe it is not an NVME 
device at all ? How could we check if it is a PCIe device instead ?

One last remark :
134217728 -> 0x0800 0000 -> 0b00001000 00000000 00000000 00000000
But 0b00001000 00000000 is 2048.
It may be a byte order issue ? or endianess ? like what we may have with 02 80 01 -> 02 08 01 
Could we force the page size to see what it gives ?

Thank you !