Re: [PATCH 2/2] arm/virt/acpi: remove _ADR from devices identified by _HID

From: "Michael S. Tsirkin" <mst@redhat.com>
To: Corey Minyard <cminyard@mvista.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
	qemu-devel@nongnu.org, Shannon Zhao <shannon.zhaosl@gmail.com>,
	qemu-arm@nongnu.org, Igor Mammedov <imammedo@redhat.com>,
	Heyi Guo <guoheyi@huawei.com>,
	wanghaibin.wang@huawei.com
Subject: Re: [PATCH 2/2] arm/virt/acpi: remove _ADR from devices identified by _HID
Date: Mon, 6 Jan 2020 04:39:51 -0500	[thread overview]
Message-ID: <20200106043916-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20200105225420.GJ6497@minyard.net>

On Sun, Jan 05, 2020 at 04:54:20PM -0600, Corey Minyard wrote:
> On Sun, Jan 05, 2020 at 07:33:55AM -0500, Michael S. Tsirkin wrote:
> > On Thu, Dec 19, 2019 at 02:47:59PM +0800, Heyi Guo wrote:
> > > According to ACPI spec, _ADR should be used for device which is on a
> > > bus that has a standard enumeration algorithm. It does not make sense
> > > to have a _ADR object for devices which already have _HID and will be
> > > enumerated by OSPM.
> > > 
> > > Signed-off-by: Heyi Guo <guoheyi@huawei.com>
> > 
> > Are you sure? I would think this depends on the ID and the device
> > really. E.g. PCI devices all are expected to have _ADR and some of them
> > have a _HID.
> 
> That's my understanding, too.
> 
> > 
> > CC Corey who added a device with both HID and ADR to x86 recenly.
> > 
> > Apropos Corey, why was HID APP0005 chosen?
> 
> I don't remember.  I thought I had looked it up someplace, but I didn't
> document it.
> 
> >From reading the spec, I believe you could safely delete the _HID and it
> would be fine.  However, I don't see anything that says it can't be
> there, either.  But it is extraneous.
> 
> Searching on the web a bit, I see that the APP0005 has confused windows.

Could you post the link you found pls?

> It does look to be wrong.  Maybe deleting it would be a good idea.
> 
> -corey
> 
> > 
> > > ---
> > > Cc: Shannon Zhao <shannon.zhaosl@gmail.com>
> > > Cc: Peter Maydell <peter.maydell@linaro.org>
> > > Cc: "Michael S. Tsirkin" <mst@redhat.com>
> > > Cc: Igor Mammedov <imammedo@redhat.com>
> > > Cc: qemu-arm@nongnu.org
> > > Cc: qemu-devel@nongnu.org
> > > ---
> > >  hw/arm/virt-acpi-build.c          |   8 --------
> > >  tests/data/acpi/virt/DSDT         | Bin 18449 -> 18426 bytes
> > >  tests/data/acpi/virt/DSDT.memhp   | Bin 19786 -> 19763 bytes
> > >  tests/data/acpi/virt/DSDT.numamem | Bin 18449 -> 18426 bytes
> > >  4 files changed, 8 deletions(-)
> > > 
> > > diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> > > index 9f4c7d1889..be752c0ad8 100644
> > > --- a/hw/arm/virt-acpi-build.c
> > > +++ b/hw/arm/virt-acpi-build.c
> > > @@ -78,11 +78,6 @@ static void acpi_dsdt_add_uart(Aml *scope, const MemMapEntry *uart_memmap,
> > >                               AML_EXCLUSIVE, &uart_irq, 1));
> > >      aml_append(dev, aml_name_decl("_CRS", crs));
> > >  
> > > -    /* The _ADR entry is used to link this device to the UART described
> > > -     * in the SPCR table, i.e. SPCR.base_address.address == _ADR.
> > > -     */
> > > -    aml_append(dev, aml_name_decl("_ADR", aml_int(uart_memmap->base)));
> > > -
> > >      aml_append(scope, dev);
> > >  }
> > >  
> > > @@ -170,7 +165,6 @@ static void acpi_dsdt_add_pci(Aml *scope, const MemMapEntry *memmap,
> > >      aml_append(dev, aml_name_decl("_CID", aml_string("PNP0A03")));
> > >      aml_append(dev, aml_name_decl("_SEG", aml_int(0)));
> > >      aml_append(dev, aml_name_decl("_BBN", aml_int(0)));
> > > -    aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
> > >      aml_append(dev, aml_name_decl("_UID", aml_string("PCI0")));
> > >      aml_append(dev, aml_name_decl("_STR", aml_unicode("PCIe 0 Device")));
> > >      aml_append(dev, aml_name_decl("_CCA", aml_int(1)));
> > > @@ -334,7 +328,6 @@ static void acpi_dsdt_add_gpio(Aml *scope, const MemMapEntry *gpio_memmap,
> > >  {
> > >      Aml *dev = aml_device("GPO0");
> > >      aml_append(dev, aml_name_decl("_HID", aml_string("ARMH0061")));
> > > -    aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
> > >      aml_append(dev, aml_name_decl("_UID", aml_int(0)));
> > >  
> > >      Aml *crs = aml_resource_template();
> > > @@ -364,7 +357,6 @@ static void acpi_dsdt_add_power_button(Aml *scope)
> > >  {
> > >      Aml *dev = aml_device(ACPI_POWER_BUTTON_DEVICE);
> > >      aml_append(dev, aml_name_decl("_HID", aml_string("PNP0C0C")));
> > > -    aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
> > >      aml_append(dev, aml_name_decl("_UID", aml_int(0)));
> > >      aml_append(scope, dev);
> > >  }
> > > diff --git a/tests/data/acpi/virt/DSDT b/tests/data/acpi/virt/DSDT
> > 
> > 
> > Please do not include binary changes in acpi patches.
> > 
> > See comment at the top of tests/bios-tables-test.c for documentation
> > on how to update these.
> > 
> > -- 
> > MST
> > 