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SubjectRe: [PATCH v2 5/7] platform/x86: ideapad-laptop: Expose camera_power only if supported
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Hi Eray,

On 11/15/22 21:43, Hans de Goede wrote:
> Hi Eray,
>
> On 10/29/22 14:03, Eray Orçunus wrote:
>> IdeaPads dropped support for VPCCMD_W_CAMERA somewhere between 2014-2016,
>> none of the IdeaPads produced after that I tested supports it. Fortunately
>> I found a way to check it; if the DSDT has camera device(s) defined, it
>> shouldn't have working VPCCMD_W_CAMERA, thus camera_power shouldn't be
>> exposed to sysfs. To accomplish this, walk the ACPI namespace in
>> ideapad_check_features and check the devices starting with "CAM".
>> Tested on 520-15IKB and Legion Y520, which successfully didn't expose
>> the camera_power attribute.
>>
>> Link: https://www.spinics.net/lists/platform-driver-x86/msg26147.html
>> Signed-off-by: Eray Orçunus <erayorcunus@gmail.com>
>> ---
>> drivers/platform/x86/ideapad-laptop.c | 52 ++++++++++++++++++++++++++-
>> 1 file changed, 51 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/platform/x86/ideapad-laptop.c b/drivers/platform/x86/ideapad-laptop.c
>> index f3d4f2beda07..e8c088e7a53d 100644
>> --- a/drivers/platform/x86/ideapad-laptop.c
>> +++ b/drivers/platform/x86/ideapad-laptop.c
>> @@ -149,6 +149,7 @@ struct ideapad_private {
>> bool fn_lock : 1;
>> bool hw_rfkill_switch : 1;
>> bool kbd_bl : 1;
>> + bool cam_ctrl_via_ec : 1;
>> bool touchpad_ctrl_via_ec : 1;
>> bool usb_charging : 1;
>> } features;
>> @@ -163,6 +164,24 @@ static bool no_bt_rfkill;
>> module_param(no_bt_rfkill, bool, 0444);
>> MODULE_PARM_DESC(no_bt_rfkill, "No rfkill for bluetooth.");
>>
>> +static acpi_status acpi_find_device_callback(acpi_handle handle, u32 level,
>> + void *context, void **return_value)
>> +{
>> + struct acpi_buffer ret_buf;
>> + char buffer[8];
>> +
>> + ret_buf.length = sizeof(buffer);
>> + ret_buf.pointer = buffer;
>> +
>> + if (ACPI_SUCCESS(acpi_get_name(handle, ACPI_SINGLE_NAME, &ret_buf)))
>> + if (strstarts(ret_buf.pointer, context)) {
>> + *return_value = handle;
>> + return AE_CTRL_TERMINATE;
>> + }
>> +
>> + return AE_OK;
>> +}
>> +
>> /*
>> * ACPI Helpers
>> */
>> @@ -675,7 +694,7 @@ static umode_t ideapad_is_visible(struct kobject *kobj,
>> bool supported = true;
>>
>> if (attr == &dev_attr_camera_power.attr)
>> - supported = test_bit(CFG_CAP_CAM_BIT, &priv->cfg);
>> + supported = priv->features.cam_ctrl_via_ec;
>> else if (attr == &dev_attr_conservation_mode.attr)
>> supported = priv->features.conservation_mode;
>> else if (attr == &dev_attr_fan_mode.attr)
>> @@ -1527,6 +1546,37 @@ static void ideapad_check_features(struct ideapad_private *priv)
>>
>> priv->features.hw_rfkill_switch = dmi_check_system(hw_rfkill_list);
>>
>> + /*
>> + * Some IdeaPads have camera switch via EC (mostly older ones),
>> + * some don't. Fortunately we know that if DSDT contains device
>> + * object for the camera, camera isn't switchable via EC.
>> + * So, let's walk the namespace and try to find CAM* object.
>> + * If we can't find it, set cam_ctrl_via_ec to true.
>> + */
>> +
>> + priv->features.cam_ctrl_via_ec = false;
>
> There is no need to explicitly set this to false since the entire
> struct is allocated with kzalloc() and a bunch of other features
> flags are also not explicitly set to false. Please drop this line.
>
>> +
>> + if (test_bit(CFG_CAP_CAM_BIT, &priv->cfg)) {
>> + acpi_handle temp_handle = NULL;
>> + acpi_handle pci_handle;
>> + acpi_status status;
>> +
>> + status = acpi_get_handle(handle, "^^^", &pci_handle);
>> + if (ACPI_SUCCESS(status)) {
>> + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, pci_handle,
>> + ACPI_UINT32_MAX,
>> + acpi_find_device_callback,
>> + NULL, "CAM",
>> + &temp_handle);
>
> Why not just use acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, ... ?
>
> The PCI root is usually pretty much the only object under the root anyways
> and this way you can avoid the acpi_get_handle() call + its error handling,
> so using ACPI_ROOT_OBJECT would lead to a nice cleanup.

Note when you send out a new version of this patch + patch 6/7,
please base it on top of my current review-hans branch since
a bunch of other ideapad-laptop changes have landed there.

Regards,

Hans


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