[Nouveau] [PATCH] gpu/nouveau/nouveau_acpi.c: Fix Type Mismatch ACPI warning

Pierre Moreau pierre.morrow at free.fr
Thu May 19 09:49:15 UTC 2016


Hello Marcos,

I sent a serie a year ago to fix some of the ACPI handling in Nouveau and add
runtime pm support for laptops with an Apple GMUX (see [0], and especially [1]
and [2]). I was told that a more generic work for the runtime pm was in the
work, so I let the whole serie slip away. I was thinking of resubmitting the
serie without the runtime pm additions, to at least fix those warning/error
messages. I thought I had a patch to fix this issue in my serie, but going
through it again, it looks like I did not.
Note that even, though the spec says the 4th argument should be a package, some
old BIOSes expect a different type, like a buffer (see the comment above [5]; I
think there was also a comment about it in the spec, but I can’t find it
anymore).

I added some comments below. I’ll test this patch tonight, to see how it works
on my laptop as I think it expects a buffer as 4th argument.

Thank you!

Regards,
Pierre


[0]: https://lists.freedesktop.org/archives/dri-devel/2015-May/083444.html
[1]: https://lists.freedesktop.org/archives/dri-devel/2015-May/083448.html
[2]: https://lists.freedesktop.org/archives/dri-devel/2015-May/083449.html

On 09:42 PM - May 18 2016, Marcos Paulo de Souza wrote:
> nouveau_optimus_dsm is using ACPI_TYPE_BUFFER, and this triggers warnings on ACPI:
> [    7.730564] ACPI: \_SB_.PCI0.RP05.PEGP: failed to evaluate _DSM
> [    7.730570] ACPI Warning: \_SB_.PCI0.RP05.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (201509    30/nsarguments-95)
> 
> To fix it, change ACPI_TYPE_BUFFER to ACPI_TYPE_PACKAGE, as the warning tells to do.
> 
> Signed-off-by: Marcos Paulo de Souza <marcos.souza.org at gmail.com>
> ---
> 
> After booting my Asus Laptop, and after a suspend/resume too, dmesg shows warnings:
> [    1.633361] ACPI Warning: \_SB_.PCI0.RP05.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20150930/nsarguments-95)
> [    1.633434] ACPI Warning: \_SB_.PCI0.RP05.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20150930/nsarguments-95)
> [    7.730176] ACPI Warning: \_SB_.PCI0.RP05.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20150930/nsarguments-95)
> [    7.730564] ACPI: \_SB_.PCI0.RP05.PEGP: failed to evaluate _DSM
> [    7.730570] ACPI Warning: \_SB_.PCI0.RP05.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20150930/nsarguments-95)
> [   49.732059] ACPI Warning: \_SB_.PCI0.RP05.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20150930/nsarguments-95)
> [   49.732424] ACPI: \_SB_.PCI0.RP05.PEGP: failed to evaluate _DSM
> [   49.732430] ACPI Warning: \_SB_.PCI0.RP05.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20150930/nsarguments-95)
> [   74.366300] ACPI Warning: \_SB_.PCI0.RP05.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20150930/nsarguments-95)
> [   74.366657] ACPI: \_SB_.PCI0.RP05.PEGP: failed to evaluate _DSM
> [   74.366663] ACPI Warning: \_SB_.PCI0.RP05.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20150930/nsarguments-95)
> [  140.357789] ACPI Warning: \_SB_.PCI0.RP05.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20150930/nsarguments-95)
> [  140.358532] ACPI: \_SB_.PCI0.RP05.PEGP: failed to evaluate _DSM
> [  140.358547] ACPI Warning: \_SB_.PCI0.RP05.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20150930/nsarguments-95)

Out of curiosity, which GPU(s) do you have in your laptop? I guess there is at
least an NVIDIA one, but is it an Optimus configuration? And if so, does the
unused card go automatically to sleep after a few seconds?

> 
> I don't know if this is the right thing to do, I just looked at intel_acpi.c to check how to use/check for ACPI Package.
> The patch below silenced the "type mismatch" warnings, and some of the "evaluated _DSM" ones.
> 
> If this is not the right approach, please let me know how to fix it, I don't have knowledge in ACPI, but I really want to help.
> 
>  drivers/gpu/drm/nouveau/nouveau_acpi.c | 14 +-------------
>  1 file changed, 1 insertion(+), 13 deletions(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c
> index cdf5227..f04aef3 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_acpi.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c
> @@ -73,22 +73,10 @@ static const char nouveau_op_dsm_muid[] = {
>  
>  static int nouveau_optimus_dsm(acpi_handle handle, int func, int arg, uint32_t *result)
>  {
> -	int i;
>  	union acpi_object *obj;
> -	char args_buff[4];
> -	union acpi_object argv4 = {
> -		.buffer.type = ACPI_TYPE_BUFFER,
> -		.buffer.length = 4,
> -		.buffer.pointer = args_buff
> -	};
> -
> -	/* ACPI is little endian, AABBCCDD becomes {DD,CC,BB,AA} */
> -	for (i = 0; i < 4; i++)
> -		args_buff[i] = (arg >> i * 8) & 0xFF;
> -
>  	*result = 0;
>  	obj = acpi_evaluate_dsm_typed(handle, nouveau_op_dsm_muid, 0x00000100,
> -				      func, &argv4, ACPI_TYPE_BUFFER);
> +				      func, NULL, ACPI_TYPE_PACKAGE);

The last parameter you give to `acpi_evaluate_dsm_typed()` is the return type
you expect (see [3]), which will be a buffer if func is 0, and is
implementation dependent otherwise (see section 9.14.1 _DSM of [4]). So you
don’t want to change it to ACPI_TYPE_PACKAGE. If you look at the implementation
of `acpi_evaluate_dsm()` (which is called by `acpi_evaluate_dsm_typed()`), it
will automatically create a package for the 4th argument, if you pass it a NULL
pointer (see [5]).

[3]: https://github.com/torvalds/linux/blob/46c13450624e36302547a2ac3695f2350fe7ffc3/include/acpi/acpi_bus.h#L69
[4]: http://www.acpi.info/DOWNLOADS/ACPI_5_Errata%20A.pdf
[5]: https://github.com/torvalds/linux/blob/46c13450624e36302547a2ac3695f2350fe7ffc3/drivers/acpi/utils.c#L628

>  	if (!obj) {
>  		acpi_handle_info(handle, "failed to evaluate _DSM\n");
>  		return AE_ERROR;
> -- 
> 2.5.5
> 
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> dri-devel at lists.freedesktop.org
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