Re: Fixing X220 Video The Right Way

On 02/28/13 09:09, John Baldwin wrote:
> On Thursday, February 28, 2013 8:15:46 am matt wrote:
>> On 02/27/13 12:27, John Baldwin wrote:
>>> On Wednesday, February 27, 2013 1:35:43 pm matt wrote:
>>>> On 02/27/13 09:00, John Baldwin wrote:
>>>>> If that is true, it's because your BIOS is lying. Do you have a URL to
>>>>> your ASL lying around already?
>>>> Too big for pastebin :( +500k
>>>>
>>>> https://docs.google.com/file/d/0B6YlMzJxarGbVnotLUdNWWNTVG8/edit?usp=sharing
>>> Here is where I find _DOD and _DOS methods:
>>>
>>>          Device (PCI0)
>>>              Device (VID)
>>>                  Name (_ADR, 0x00020000)  // _ADR: Address
>>>                  Method (_DOS, 1, NotSerialized)  // _DOS: Disable Output Switching
>>>                  Method (_DOD, 0, NotSerialized)  // _DOD: Display Output Devices
>>>              Device (PEG)
>>>                  Name (_ADR, 0x00010000)  // _ADR: Address
>>>                  Device (VID)
>>>                      Name (_ADR, 0x00)  // _ADR: Address
>>>                      Method (_DOS, 1, NotSerialized)  // _DOS: Disable Output Switching
>>>                      Method (_DOD, 0, NotSerialized)  // _DOD: Display Output Devices
>>>
>>> PCI0.VID is a PCI device at pci0:0:2:0.
>>> PCI0.PEG would be a PCI-PCI bridge at pci0:0:1:0.
>>> It would have a child device at 0:0 that would be PCI0.PEG.VID.  Does the X220
>>> have a switchable GPU (e.g. it has built-in Intel graphics, but also has an
>>> Nvidia GPU or some such?).  If so, I imagine that PCI0.VID is the Intel graphics
>>> and PEG is the non-Intel.  The output of 'pciconf -lcv' would be useful to determine
>>> that.  If both PCI devices exist you shoudl have both acpi_video0 and acpi_video1.
>>> However, it may be that the acpi_video driver doesn't cope well with having multiple
>>> devices.
>> Only Intel graphics, there is no option for switchable graphics.
>> I initially thought that PEG was for Optimus usage, and left in the bios 
>> by accident (i.e. Lenovo using a generic DSDT for many machines)
>>
>> Here is pciconf -lcf, truncated
>> hostb0_at_pci0:0:0:0:    class=0x060000 card=0x21da17aa chip=0x01048086 
>> rev=0x09 hdr=0x00
>>      vendor     = 'Intel Corporation'
>>      device     = '2nd Generation Core Processor Family DRAM Controller'
>>      class      = bridge
>>      subclass   = HOST-PCI
>>      cap 09[e0] = vendor (length 12) Intel cap 0 version 1
>> vgapci0_at_pci0:0:2:0:    class=0x030000 card=0x21da17aa chip=0x01268086 
>> rev=0x09 hdr=0x00
>>      vendor     = 'Intel Corporation'
>>      device     = '2nd Generation Core Processor Family Integrated 
>> Graphics Controller'
>>      class      = display
>>      subclass   = VGA
>>      cap 05[90] = MSI supports 1 message enabled with 1 message
>>      cap 01[d0] = powerspec 2  supports D0 D3  current D0
>>      cap 13[a4] = PCI Advanced Features: FLR TP
>> none0_at_pci0:0:22:0:    class=0x078000 card=0x21da17aa chip=0x1c3a8086 
>> rev=0x04 hdr=0x00
>>      vendor     = 'Intel Corporation'
>>
>> As you can see there is no device at pci0:0:1:0. So no dev_t with for 
>> acpi_video to probe or attach to.
>>
>> Nonetheless, only PEGs ACPI methods work, which is quite broken. This is 
>> true for a large number of Lenovo devices, back to x61 (non-attaching 
>> AGP adr) and probably including some other x series and t series.
>>
>> Unfortunately the ASL will not compile which makes fixing the DSDT an 
>> exercise in fixing broken ACPI.
>>
>> What I find interesting is that as far as I can tell, there's no special 
>> case handling for this device in Linux, yet backlight controls work out 
>> of the box since about 3.0. Installing Linux as the OSI via loader.conf 
>> is not the issue, unfortunately, nor Windows 2006 (/WVIS) or Windows 
>> 2009 (/WIN7). I get correct (for platform) behavior when I call PEGs 
>> _BCM... :(
>>
>> Is Linux getting this to work by doing it wrong, essentially?
> Yes.  I think the best way to fix this is to add a way to specify a
> hint to override the ACPI path associated with a PCI device.  Something
> like:
>
> hw.pci0.0.2.0.handle="\_SB_.PCI0.PEG.VID"
>
> I think this patch should do the trick:
>
> Index: sys/dev/acpica/acpi_pci.c
> ===================================================================
> --- acpi_pci.c	(revision 247320)
> +++ acpi_pci.c	(working copy)
> _at__at_ -264,6 +264,40 _at__at_ acpi_pci_save_handle(ACPI_HANDLE handle, UINT32 le
>  	return_ACPI_STATUS (AE_OK);
>  }
>  
> +static void
> +acpi_pci_override_handles(device_t dev)
> +{
> +	struct acpi_pci_devinfo *dinfo;
> +	device_t *devlist;
> +	int error, i, numdevs;
> +	char tunable_name[64], *path;
> +	ACPI_HANDLE handle;
> +
> +	error = device_get_children(dev, &devlist, &numdevs);
> +	if (error)
> +		return;
> +	for (i = 0; i < numdevs; i++) {
> +		dinfo = device_get_ivars(devlist[i]);
> +		snprintf(tunable_name, sizeof(tunable_name),
> +		    "hw.pci%d.%d.%d.%d.handle", dinfo->ap_dinfo.cfg.domain,
> +		    dinfo->ap_dinfo.cfg.bus, dinfo->ap_dinfo.cfg.slot,
> +		    dinfo->ap_dinfo.cfg.func);
> +		path = getenv(tunable_name);
> +		if (path == NULL)
> +			continue;
> +		if (ACPI_SUCCESS(AcpiGetHandle(NULL, path, &handle))) {
> +			device_printf(dev,
> +			    "Forcing device at %d.%d to use path %s\n",
> +			    dinfo->ap_dinfo.cfg.slot,
> +			    dinfo->ap_dinfo.cfg.func, path);
> +			dinfo->ap_handle = handle;
> +			acpi_pci_update_device(handle, devlist[i]);
> +		}
> +		freeenv(path);
> +	}
> +	free(devlist, M_TEMP);
> +}
> +
>  static int
>  acpi_pci_probe(device_t dev)
>  {
> _at__at_ -306,5 +340,10 _at__at_ acpi_pci_attach(device_t dev)
>  	AcpiWalkNamespace(ACPI_TYPE_DEVICE, acpi_get_handle(dev), 1,
>  	    acpi_pci_save_handle, NULL, dev, NULL);
>  
> +	/*
> +	 * Perform another pass over child devices to allow their
> +	 * handles to be overridden via a hint from the user.
> +	 */
> +	acpi_pci_override_handles(dev);
>  	return (bus_generic_attach(dev));
>  }
>
>
Initial attempt with this patch failed to change the result in devinfo
-rv...I will hopefully have more info tonight.

Thanks,

Matt