Re: [PATCH] x86/PCI: Disable E820 reserved region clipping for Clevo NL4XLU laptops

[Bjorn Helgaas <helgaas@kernel.org>]

On Sun, Dec 04, 2022 at 10:42:38AM +0100, Hans de Goede wrote:
> On 12/2/22 22:58, Bjorn Helgaas wrote:
> > On Wed, Oct 12, 2022 at 10:23:12AM +0200, Hans de Goede wrote:
> >> On 10/11/22 19:40, Bjorn Helgaas wrote:
> >>> On Mon, Oct 10, 2022 at 05:02:06PM +0200, Hans de Goede wrote:
> >>>> Clevo NL4XLU barebones have the same E820 reservation covering
> >>>> the entire _CRS 32-bit window issue as the Lenovo *IIL* and
> >>>> Clevo X170KM-G models, relevant dmesg bits (with pci=no_e820):
> >>>> ...
> >>>> Add a no_e820 quirk for these models to fix the touchpad not working
> >>>> (due to Linux being unable to assign a PCI BAR for the i2c-controller).
> ...

> As I mentioned in the email-thread about that patch-series (and there
> now is dmesg E820 output to confirm this) your generic fix will
> unfortunately only work when people boot in EFI mode. It will still
> be good to have the generic fix of course.
> 
> But maybe we should also add this quirk to make sure these
> Clevo-s also work properly when booted in BIOS CSM mode ?

Yes, if they can boot in CSM mode, we should probably add the quirk.
But Florent doesn't see a way to boot his Clevo NL41LU2/NL4XLU in CSM
mode, so I think we can postpone adding the quirk until we find a
machine where it makes a difference:

  https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1948811/comments/8

I added a note to https://bugzilla.kernel.org/show_bug.cgi?id=216565
to that effect.

> >>>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=216565
> >>>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> >>>> ---
> >>>>  arch/x86/pci/acpi.c | 13 +++++++++++++
> >>>>  1 file changed, 13 insertions(+)
> >>>>
> >>>> diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
> >>>> index 2f82480fd430..45ef65d31a40 100644
> >>>> --- a/arch/x86/pci/acpi.c
> >>>> +++ b/arch/x86/pci/acpi.c
> >>>> @@ -189,6 +189,19 @@ static const struct dmi_system_id pci_crs_quirks[] __initconst = {
> >>>>  			DMI_MATCH(DMI_BOARD_NAME, "X170KM-G"),
> >>>>  		},
> >>>>  	},
> >>>> +
> >>>> +	/*
> >>>> +	 * Clevo NL4XLU barebones have the same E820 reservation covering
> >>>> +	 * the entire _CRS 32-bit window issue as the Lenovo *IIL* models.
> >>>> +	 * See https://bugzilla.kernel.org/show_bug.cgi?id=216565
> >>>> +	 */
> >>>> +	{
> >>>> +		.callback = set_no_e820,
> >>>> +		.ident = "Clevo NL4XLU Barebone",
> >>>> +		.matches = {
> >>>> +			DMI_MATCH(DMI_BOARD_NAME, "NL4XLU"),
> >>>> +		},
> >>>> +	},
> >>>>  	{}
> >>>>  };