ahci + intel iGPU problems

[Hannes Reinecke]

On 5/16/25 15:42, Niklas Cassel wrote:
> Hello there,
> 
> This bug report came in to Serial ATA bugzilla recently:
> https://bugzilla.kernel.org/show_bug.cgi?id=220111
> 
> The user claims to have bisected a problem to commit
> 7627a0edef54 ("ata: ahci: Drop low power policy board type")
> 
> However, when looking at the dmesg from:
> https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14213
> (see dmesg inlined at the end of this email), I cannot see a
> single AHCI, SCSI or libata timeout, or any other error that
> would indicate that there is a problem with the drive.
> 
> I do however see a bunch of i915 timeouts.
> 
The nasty thing about i915 is that is reconfigures the _root bride_.
As the i915 device is always built-in, the driver 'knows' what's
best for the root bridge, and reconfigures it.
(IIRC this happens if you several outputs and for some reason they
are not configured correctly.)
And if you are particularly unlucky the driver configures it wrong,
killing other devices in the process. That happened to us once, where
the i915 driver ended up killing the NVMe device.

Please check the i915 output configuration, and try to get a PCI
configuration readout before and after loading the i915 driver.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare at suse.de                                +49 911 74053 688
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