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From:   "Rafael J. Wysocki" <rjw@rjwysocki.net>
To:     Bjorn Helgaas <bhelgaas@google.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Linux PCI <linux-pci@vger.kernel.org>,
        Patrick Talbert <ptalbert@redhat.com>
Subject: Re: [Bug] SD card reader in Acer Aspire S5 broken in 4.20-rc
Date:   Mon, 26 Nov 2018 23:37:20 +0100
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On Monday, November 26, 2018 7:03:58 PM CET Rafael J. Wysocki wrote:
> Hi Bjorn,
> 
> The SD card reader in my Acer Aspire S5 doesn't work with 4.20-rc.
> 
> Here's what lspci -v says about it (in a bad kernel):
> 
> 02:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5209 PCI Express Card Reader 
> (rev 01)
>         Subsystem: Acer Incorporated [ALI] Device 0704
>         Flags: bus master, fast devsel, latency 0, IRQ 35
>         Memory at d9001000 (32-bit, non-prefetchable) [size=4K]
>         Capabilities: [40] Power Management version 3
>         Capabilities: [50] MSI: Enable+ Count=1/1 Maskable- 64bit+
>         Capabilities: [70] Express Endpoint, MSI 00
>         Capabilities: [100] Advanced Error Reporting
>         Capabilities: [140] Device Serial Number 00-00-00-01-00-4c-e0-00
>         Kernel driver in use: rtsx_pci
>         Kernel modules: rtsx_pci
> 
> When it doesn't work, it doesn't generate any interrupts on device insertion
> and removal and this seems to be reproducible 100% of the time.
> 
> Bisection turned up
> 
> commit de468b755464426c276df2daf1e54bcd64186020
> Merge: b1801bf05964 d6112f8def51
> Author: Bjorn Helgaas <bhelgaas@google.com>
> Date:   Sat Oct 20 11:45:28 2018 -0500
> 
>     Merge branch 'pci/enumeration'
>     
>       - Remove x86 and arm64 node-local allocation for host bridge structures
>         (Punit Agrawal)
>     
>       - Pay attention to device-specific _PXM node values (Jonathan Cameron)
>     
>       - Support new Immediate Readiness bit (Felipe Balbi)
>     
>     * pci/enumeration:
>       PCI: Add support for Immediate Readiness
>       ACPI/PCI: Pay attention to device-specific _PXM node values
>       x86/PCI: Remove node-local allocation when initialising host controller
>       arm64: PCI: Remove node-local allocations when initialising host controller
> 
> as the first bad commit, but the "PCI: Add support for Immediate Readiness"
> one was tested as "good" (full bisect log is attached).
> 
> I wonder if you have any ideas on what to check?

So reverting 17c91487364f (PCI/ASPM: Do not initialize link state when
aspm_disabled is set) on top of 4.20-rc4 makes the problem go away.

I guess that the device in question needs pcie_aspm_cap_init() to be
called for it even though the FADT says "NO_ASPM".

Thanks,
Rafael