Hi Leo and Mario,
On Wed, Nov 26, 2025 at 05:05:15PM +0800, Yo-Jung Leo Lin (AMD) wrote:
> Add a uma/ directory containing two sysfs files as interfaces to
> inspect or change UMA carveout size. These files are:
>
> - uma/carveout_options: a read-only file listing all the available
> UMA allocation options and their index.
>
> - uma/carveout: a file that is both readable and writable. On read,
> it shows the index of the current setting. Writing a valid index
> into this file allows users to change the UMA carveout size to that
> option on the next boot.
>
> Co-developed-by: Mario Limonciello (AMD) <[email protected]>
> Signed-off-by: Mario Limonciello (AMD) <[email protected]>
> Signed-off-by: Yo-Jung Leo Lin (AMD) <[email protected]>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c | 137
> +++++++++++++++++++++++++++++++
> 1 file changed, 137 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> index bce9027fa241..c3b7b8c91919 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> @@ -30,6 +30,7 @@
> #include <linux/power_supply.h>
> #include <linux/pm_runtime.h>
> #include <linux/suspend.h>
> +#include <linux/device.h>
> #include <acpi/video.h>
> #include <acpi/actbl.h>
>
> @@ -1246,6 +1247,135 @@ int amdgpu_acpi_get_mem_info(struct amdgpu_device
> *adev, int xcc_id,
> return -ENOENT;
> }
>
> +static ssize_t carveout_options_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct amdgpu_uma_carveout_info *uma_info =
> &amdgpu_acpi_priv.atcs.uma_info;
> + uint32_t memory_carved;
> + ssize_t size = 0;
> +
> + if (!uma_info || !uma_info->num_entries)
> + return -ENODEV;
> +
> + for (int i = 0; i < uma_info->num_entries; i++) {
> + memory_carved = uma_info->entries[i].memory_carved_mb;
> + if (memory_carved >= SZ_1G/SZ_1M) {
> + size += sysfs_emit_at(buf, size, "%d: %s (%u GB)\n",
> + i,
> + uma_info->entries[i].name,
> + memory_carved >> 10);
> + } else {
> + size += sysfs_emit_at(buf, size, "%d: %s (%u MB)\n",
> + i,
> + uma_info->entries[i].name,
> + memory_carved);
> + }
> + }
> +
> + return size;
> +}
> +static DEVICE_ATTR_RO(carveout_options);
> +
> +static ssize_t carveout_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + return sysfs_emit(buf, "%u\n",
> amdgpu_acpi_priv.atcs.uma_info.uma_option_index);
> +}
> +
> +static ssize_t carveout_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct amdgpu_uma_carveout_info *uma_info =
> &amdgpu_acpi_priv.atcs.uma_info;
> + struct drm_device *ddev = dev_get_drvdata(dev);
> + struct amdgpu_device *adev = drm_to_adev(ddev);
> + struct amdgpu_uma_carveout_option *opt;
> + unsigned long val;
> + uint8_t flags;
> + int r;
> +
> + r = kstrtoul(buf, 10, &val);
> + if (r)
> + return r;
> +
> + if (val >= uma_info->num_entries)
> + return -EINVAL;
> +
> + opt = &uma_info->entries[val];
> +
> + if (!(opt->flags & AMDGPU_UMA_FLAG_AUTO) &&
> + !(opt->flags & AMDGPU_UMA_FLAG_CUSTOM)) {
> + drm_err_once(ddev, "Option %ul not supported due to lack of
> Custom/Auto flag", r);
I'm not an expert in drm or gpu related stuff.
But r is always 0 here. Also, its type is int, so it doesn't match the
%ul format specifier.
I guess you mean val instead of r here?
Regards,
Kuan-Wei
> + return -EINVAL;
> + }
> +
> + flags = opt->flags;
> + flags &= ~((flags & AMDGPU_UMA_FLAG_AUTO) >> 1);
> +
> + guard(mutex)(&uma_info->update_lock);
> +
> + r = amdgpu_acpi_set_uma_allocation_size(adev, val, flags);
> + if (r)
> + return r;
> +
> + uma_info->uma_option_index = val;
> +
> + return count;
> +}
> +static DEVICE_ATTR_RW(carveout);
> +
> +static struct attribute *amdgpu_uma_attrs[] = {
> + &dev_attr_carveout.attr,
> + &dev_attr_carveout_options.attr,
> + NULL
> +};
> +
> +const struct attribute_group amdgpu_uma_attr_group = {
> + .name = "uma",
> + .attrs = amdgpu_uma_attrs
> +};
> +
> +static int amdgpu_acpi_uma_option_init(struct amdgpu_device *adev)
> +{
> + struct amdgpu_atcs *atcs = &amdgpu_acpi_priv.atcs;
> + int rc;
> +
> + if (!atcs->functions.set_uma_allocation_size)
> + return -ENODEV;
> +
> + rc = amdgpu_atomfirmware_get_uma_carveout_info(adev, &atcs->uma_info);
> + if (rc) {
> + drm_dbg(adev_to_drm(adev),
> + "Failed to parse UMA carveout info from VBIOS: %d\n",
> rc);
> + goto out_info;
> + }
> +
> + mutex_init(&atcs->uma_info.update_lock);
> +
> + rc = devm_device_add_group(adev->dev, &amdgpu_uma_attr_group);
> + if (rc) {
> + drm_dbg(adev_to_drm(adev), "Failed to add UMA carveout sysfs
> interfaces %d\n", rc);
> + goto out_attr;
> + }
> +
> + return 0;
> +
> +out_attr:
> + mutex_destroy(&atcs->uma_info.update_lock);
> +out_info:
> + return rc;
> +}
> +
> +static void amdgpu_acpi_uma_option_fini(void)
> +{
> + struct amdgpu_uma_carveout_info *uma_info =
> &amdgpu_acpi_priv.atcs.uma_info;
> +
> + mutex_destroy(&uma_info->update_lock);
> + uma_info->num_entries = 0;
> +}
> +
> /**
> * amdgpu_acpi_event - handle notify events
> *
> @@ -1290,6 +1420,12 @@ static int amdgpu_acpi_event(struct notifier_block *nb,
> int amdgpu_acpi_init(struct amdgpu_device *adev)
> {
> struct amdgpu_atif *atif = &amdgpu_acpi_priv.atif;
> + int rc;
> +
> + rc = amdgpu_acpi_uma_option_init(adev);
> +
> + if (rc)
> + drm_dbg(adev_to_drm(adev), "Not creating uma carveout
> interfaces: %d", rc);
>
> if (atif->notifications.brightness_change) {
> if (adev->dc_enabled) {
> @@ -1342,6 +1478,7 @@ void amdgpu_acpi_get_backlight_caps(struct
> amdgpu_dm_backlight_caps *caps)
> void amdgpu_acpi_fini(struct amdgpu_device *adev)
> {
> unregister_acpi_notifier(&adev->acpi_nb);
> + amdgpu_acpi_uma_option_fini();
> }
>
> /**
>
> --
> 2.43.0
>
>
