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Message-ID: <d7b9167d-ddb2-4bec-b294-513010501ca9@gmail.com>
Date: Thu, 11 Dec 2025 01:27:34 +0900
From: Nitin <nitjoshi@...il.com>
To: Mario Limonciello <mario.limonciello@....com>, hansg@...nel.org,
ilpo.jarvinen@...ux.intel.com
Cc: platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
njoshi1@...ovo.com, Mark Pearson <mpearson-lenovo@...ebb.ca>
Subject: Re: [PATCH v2 2/2] platform/x86: thinkpad_acpi: Add sysfs to display
details of damaged device.
Hi Mario,
Thank you for your comments.
On 12/11/25 00:43, Mario Limonciello wrote:
> On 12/10/25 9:11 AM, Nitin Joshi wrote:
>> Add new sysfs interface to identify the impacted component with
>> location of
>> device.
>>
>> Reviewed-by: Mark Pearson <mpearson-lenovo@...ebb.ca>
>> Signed-off-by: Nitin Joshi<nitjoshi@...il.com>
>> ---
>> .../admin-guide/laptops/thinkpad-acpi.rst | 13 +-
>> drivers/platform/x86/lenovo/thinkpad_acpi.c | 112 +++++++++++++++++-
>> 2 files changed, 121 insertions(+), 4 deletions(-)
>>
>> diff --git a/Documentation/admin-guide/laptops/thinkpad-acpi.rst
>> b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
>> index 94349e5f1298..3a9190ac47d0 100644
>> --- a/Documentation/admin-guide/laptops/thinkpad-acpi.rst
>> +++ b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
>> @@ -1580,7 +1580,7 @@ Documentation/ABI/testing/sysfs-class-power.
>> Hardware damage detection capability
>> -----------------
>> -sysfs attributes: hwdd_status
>> +sysfs attributes: hwdd_status, hwdd_detail
>> Thinkpads are adding the ability to detect and report hardware
>> damage.
>> Add new sysfs interface to identify the damaged device status.
>> @@ -1594,6 +1594,17 @@ This value displays status of device damaged
>> - 0 = Not Damaged
>> - 1 = Damaged
>> +The command to check location of damaged device is::
>> +
>> + cat /sys/devices/platform/thinkpad_acpi/hwdd_detail
>> +
>> +This value displays location of damaged device having 1 line per
>> damaged "item".
>> +For example:
>> +if no damage is detected:
>> + No damage detected
>> +if damage detected:
>> + TYPE-C: Base, Right side, Center port
>> +
>> The property is read-only. If feature is not supported then sysfs
>> attribute is not created.
>> diff --git a/drivers/platform/x86/lenovo/thinkpad_acpi.c
>> b/drivers/platform/x86/lenovo/thinkpad_acpi.c
>> index 4cf365550bcb..a092d57d995d 100644
>> --- a/drivers/platform/x86/lenovo/thinkpad_acpi.c
>> +++ b/drivers/platform/x86/lenovo/thinkpad_acpi.c
>> @@ -11089,8 +11089,24 @@ static const struct attribute_group
>> auxmac_attr_group = {
>> #define HWDD_NOT_SUPPORTED BIT(31)
>> #define HWDD_SUPPORT_USBC BIT(0)
>> -#define PORT_STATUS GENMASK(7, 4)
>> -#define NUM_PORTS 4
>> +#define PORT_STATUS GENMASK(7, 4)
>> +#define LID_STATUS GENMASK(11, 8)
>> +#define BASE_STATUS GENMASK(15, 12)
>> +#define POS_STATUS GENMASK(3, 2)
>> +#define PANEL_STATUS GENMASK(1, 0)
>> +
>> +#define PORT_DETAIL_OFFSET 16
>> +
>> +#define PANEL_TOP 0
>> +#define PANEL_BASE 1
>> +#define PANEL_LEFT 2
>> +#define PANEL_RIGHT 3
>> +
>> +#define POS_LEFT 0
>> +#define POS_CENTER 1
>> +#define POS_RIGHT 2
>> +
>> +#define NUM_PORTS 4
>> static bool hwdd_support_available;
>> static bool ucdd_supported;
>> @@ -11108,7 +11124,95 @@ static int hwdd_command(int command, int
>> *output)
>> return 0;
>> }
>> -/* sysfs type-c damage detection capability */
>> +static bool display_damage(char *buf, int *count, char *type,
>> unsigned int dmg_status)
>> +{
>> + unsigned char lid_status, base_status, port_status;
>> + unsigned char loc_status, pos_status, panel_status;
>> + bool damage_detected = false;
>> + int i;
>> +
>> + port_status = FIELD_GET(PORT_STATUS, dmg_status);
>> + lid_status = FIELD_GET(LID_STATUS, dmg_status);
>> + base_status = FIELD_GET(BASE_STATUS, dmg_status);
>> + for (i = 0; i < NUM_PORTS; i++) {
>> + if (!(dmg_status & BIT(i)))
>> + continue;
>> +
>> + if (port_status & BIT(i)) {
>> + *count += sysfs_emit_at(buf, *count, "%s: ", type);
>> + loc_status = (dmg_status >> (PORT_DETAIL_OFFSET + (4 *
>> i))) & 0xF;
>> + pos_status = FIELD_GET(POS_STATUS, loc_status);
>> + panel_status = FIELD_GET(PANEL_STATUS, loc_status);
>> +
>> + if (lid_status & BIT(i))
>> + *count += sysfs_emit_at(buf, *count, "Lid, ");
>> + if (base_status & BIT(i))
>> + *count += sysfs_emit_at(buf, *count, "Base, ");
>> +
>> + switch (pos_status) {
>> + case PANEL_TOP:
>> + *count += sysfs_emit_at(buf, *count, "Top, ");
>> + break;
>> + case PANEL_BASE:
>> + *count += sysfs_emit_at(buf, *count, "Bottom, ");
>> + break;
>> + case PANEL_LEFT:
>> + *count += sysfs_emit_at(buf, *count, "Left, ");
>> + break;
>> + case PANEL_RIGHT:
>> + *count += sysfs_emit_at(buf, *count, "Right, ");
>> + break;
>> + default:
>> + pr_err("Unexpected value %d in switch statement\n",
>> pos_status);
>> + };
>> +
>> + switch (panel_status) {
>> + case POS_LEFT:
>> + *count += sysfs_emit_at(buf, *count, "Left port\n");
>> + break;
>> + case POS_CENTER:
>> + *count += sysfs_emit_at(buf, *count, "Center port\n");
>> + break;
>> + case POS_RIGHT:
>> + *count += sysfs_emit_at(buf, *count, "Right port\n");
>> + break;
>> + default:
>> + *count += sysfs_emit_at(buf, *count, "Undefined\n");
>> + break;
>> + };
>> + damage_detected = true;
>> + }
>> + }
>> + return damage_detected;
>> +}
>> +
>> +/* sysfs type-c damage detection detail */
>> +static ssize_t hwdd_detail_show(struct device *dev,
>> + struct device_attribute *attr,
>> + char *buf)
>> +{
>> + bool damage_detected = false;
>> + unsigned int damage_status;
>> + int err, count = 0;
>> +
>> +
>> + if (ucdd_supported) {
>> + /* Get USB TYPE-C damage status */
>> + err = hwdd_command(HWDD_GET_DMG_USBC, &damage_status);
>> + if (err)
>> + return err;
>> +
>> + if (display_damage(buf, &count, "Type-C", damage_status))
>> + damage_detected = true;
>> + }
>
> Since this is always visible aren't you missing a case for
> !ucdd_supported? I would think you should be returning -ENODEV.
In actual, this condition should never occur as only USB Type-C is
supported in this ASL method but i think it's ok to add this check, if
there is any benefit.
In this case, is it recommended to add such case like !ucdd_supported?
Also, if new device id like type-a etc.. is added in future then we
need to include corresponding device id supported also in this check to
make sysfs visible.
>
> Although arguably it would be better to control visibility of the
> sysfs attribute based upon ucdd_supported. You can simplify
> hwdd_detail_show() too then.
If new device id is added in future then we need to add additional flag
to control visibility of sysfs .
At this moment , i cant see anything obvious to be simplified
in hwdd_detail_show() . Did i missed something ?
>
>
>> +
>> + if (!damage_detected)
>> + count += sysfs_emit_at(buf, count, "No damage detected\n");
>> +
>> + return count;
>> +}
>> +
>> +/* sysfs typc damage detection capability */
>> static ssize_t hwdd_status_show(struct device *dev,
>> struct device_attribute *attr,
>> char *buf)
>> @@ -11134,9 +11238,11 @@ static ssize_t hwdd_status_show(struct
>> device *dev,
>> return sysfs_emit(buf, "0\n");
>> }
>> static DEVICE_ATTR_RO(hwdd_status);
>> +static DEVICE_ATTR_RO(hwdd_detail);
>> static struct attribute *hwdd_attributes[] = {
>> &dev_attr_hwdd_status.attr,
>> + &dev_attr_hwdd_detail.attr,
>> NULL
>> };
> Thank you !
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