Re: [PATCH v14 4/9] platform/x86: asus-armoury: add apu-mem control support

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

On Wed, 15 Oct 2025, Denis Benato wrote:

> From: "Luke D. Jones" <luke@ljones.dev>
> 
> Implement the APU memory size control under the asus-armoury module using
> the fw_attributes class.
> 
> This allows the APU allocated memory size to be adjusted depending on
> the users priority. A reboot is required after change.
> 
> Signed-off-by: Luke D. Jones <luke@ljones.dev>
> Signed-off-by: Denis Benato <benato.denis96@gmail.com>
> ---
>  drivers/platform/x86/asus-armoury.c        | 81 ++++++++++++++++++++++
>  include/linux/platform_data/x86/asus-wmi.h |  2 +
>  2 files changed, 83 insertions(+)
> 
> diff --git a/drivers/platform/x86/asus-armoury.c b/drivers/platform/x86/asus-armoury.c
> index 68ce2c159ae1..3b49a27e397d 100644
> --- a/drivers/platform/x86/asus-armoury.c
> +++ b/drivers/platform/x86/asus-armoury.c
> @@ -394,6 +394,86 @@ static ssize_t egpu_enable_current_value_store(struct kobject *kobj, struct kobj
>  WMI_SHOW_INT(egpu_enable_current_value, "%d\n", ASUS_WMI_DEVID_EGPU);
>  ATTR_GROUP_BOOL_CUSTOM(egpu_enable, "egpu_enable", "Enable the eGPU (also disables dGPU)");
>  
> +/* Device memory available to APU */
> +
> +/* Values map for APU memory: some looks out of order but are actually correct */
> +static u32 apu_mem_map[] = {
> +	[0] = 0x000, /* called "AUTO" on the BIOS, is the minimum available */
> +	[1] = 0x102,
> +	[2] = 0x103,
> +	[3] = 0x104,
> +	[4] = 0x105,
> +	[5] = 0x107,
> +	[6] = 0x108,
> +	[7] = 0x109,
> +	[8] = 0x106,

Is BIT(8) actually telling non-AUTO here? I mean, it's not set for the 
AUTO case. If it has this special meaning, maybe that should be left out 
of this array and handled by the show/store functions as it seems 
different for the auto depending on which way the information is being 
passed.

> +};
> +
> +static ssize_t apu_mem_current_value_show(struct kobject *kobj, struct kobj_attribute *attr,
> +					  char *buf)
> +{
> +	int err;
> +	u32 mem;
> +
> +	err = asus_wmi_get_devstate_dsts(ASUS_WMI_DEVID_APU_MEM, &mem);
> +	if (err)
> +		return err;
> +
> +	if ((mem & ASUS_WMI_DSTS_PRESENCE_BIT) == 0)
> +		return -ENODEV;
> +
> +	mem &= ~ASUS_WMI_DSTS_PRESENCE_BIT;
> +
> +	/* After 0x000 is set, a read will return 0x100 */
> +	if (mem == 0x100)
> +		return sysfs_emit(buf, "0\n");
> +
> +	for (unsigned int i = 0; i < ARRAY_SIZE(apu_mem_map); i++) {
> +		if (apu_mem_map[i] == mem)
> +			return sysfs_emit(buf, "%u\n", i);
> +	}
> +
> +	pr_warn("Unrecognised value for APU mem 0x%08x\n", mem);
> +	return sysfs_emit(buf, "%u\n", mem);

??

Should this return -EIO or something like that instead. It definitely 
looks wrong to first log it as %x and then output to sysfs as %u.

> +}
> +
> +static ssize_t apu_mem_current_value_store(struct kobject *kobj, struct kobj_attribute *attr,
> +					   const char *buf, size_t count)
> +{
> +	int result, err;
> +	u32 requested, mem;
> +
> +	result = kstrtou32(buf, 10, &requested);
> +	if (result)
> +		return result;
> +
> +	if (requested >= ARRAY_SIZE(apu_mem_map))
> +		return -EINVAL;
> +
> +	mem = apu_mem_map[requested];
> +
> +	err = asus_wmi_set_devstate(ASUS_WMI_DEVID_APU_MEM, mem, &result);
> +	if (err) {
> +		pr_warn("Failed to set apu_mem: %d\n", err);
> +		return err;
> +	}
> +
> +	pr_info("APU memory changed to %uGB, reboot required\n", requested+1);

requested + 1

Please mention GB up where the array is.

> +	sysfs_notify(kobj, NULL, attr->attr.name);
> +
> +	asus_set_reboot_and_signal_event();
> +
> +	return count;
> +}
> +
> +static ssize_t apu_mem_possible_values_show(struct kobject *kobj, struct kobj_attribute *attr,
> +					    char *buf)
> +{
> +	BUILD_BUG_ON(ARRAY_SIZE(apu_mem_map) != 9);
> +	return sysfs_emit(buf, "0;1;2;3;4;5;6;7;8\n");

You could make this future proof with a for loop and sysfs_emit_at() and 
drop the BUILD_BUG_ON(). Maybe all these multi-valued show functions could 
share a helper which does that.

> +}
> +ATTR_GROUP_ENUM_CUSTOM(apu_mem, "apu_mem", "Set available system RAM (in GB) for the APU to use");
> +
>  /* Simple attribute creation */
>  ATTR_GROUP_ENUM_INT_RO(charge_mode, "charge_mode", ASUS_WMI_DEVID_CHARGE_MODE, "0;1;2",
>  		       "Show the current mode of charging");
> @@ -414,6 +494,7 @@ static const struct asus_attr_group armoury_attr_groups[] = {
>  	{ &egpu_connected_attr_group, ASUS_WMI_DEVID_EGPU_CONNECTED },
>  	{ &egpu_enable_attr_group, ASUS_WMI_DEVID_EGPU },
>  	{ &dgpu_disable_attr_group, ASUS_WMI_DEVID_DGPU },
> +	{ &apu_mem_attr_group, ASUS_WMI_DEVID_APU_MEM },
>  
>  	{ &charge_mode_attr_group, ASUS_WMI_DEVID_CHARGE_MODE },
>  	{ &boot_sound_attr_group, ASUS_WMI_DEVID_BOOT_SOUND },
> diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
> index 10acd5d52e38..a4f6bab93a6f 100644
> --- a/include/linux/platform_data/x86/asus-wmi.h
> +++ b/include/linux/platform_data/x86/asus-wmi.h
> @@ -137,6 +137,8 @@
>  /* dgpu on/off */
>  #define ASUS_WMI_DEVID_DGPU		0x00090020
>  
> +#define ASUS_WMI_DEVID_APU_MEM		0x000600C1
> +
>  /* gpu mux switch, 0 = dGPU, 1 = Optimus */
>  #define ASUS_WMI_DEVID_GPU_MUX		0x00090016
>  #define ASUS_WMI_DEVID_GPU_MUX_VIVO	0x00090026
> 

-- 
 i.