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Date: Thu, 9 Apr 2015 15:27:56 +0300
From: Mika Westerberg <mika.westerberg@...ux.intel.com>
To: "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc: Darren Hart <dvhart@...radead.org>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4/4] ACPI / scan: Rework modalias creation when
"compatible" is present
On Thu, Apr 09, 2015 at 02:22:10AM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>
> Currently, the ACPI modalias creation covers two mutually exclusive
> cases: If the PRP0001 device ID is present in the device's list of
> ACPI/PNP IDs and the "compatible" property is present in _DSD, the
> created modalias will follow the OF rules of modalias creation.
> Otherwise, ACPI rules are used.
>
> However, that is not really desirable, because the presence of PRP0001
> in the list of device IDs generally does not preclude using other
> ACPI/PNP IDs with that device and those other IDs may be of higher
> priority. In those cases, the other IDs should take preference over
> PRP0001 and therefore they also should be present in the modalias.
>
> For this reason, rework the modalias creation for ACPI so that it
> shows both the ACPI-style and OF-style modalias strings if the
> device has a non-empty list of ACPI/PNP IDs (other than PNP0001)
^^^^^^^
Typo
> and a valid "compatible" property at the same time.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
> drivers/acpi/scan.c | 204 ++++++++++++++++++++++++++++++----------------------
> 1 file changed, 120 insertions(+), 84 deletions(-)
>
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -122,8 +122,8 @@ int acpi_scan_add_handler_with_hotplug(s
> * -EINVAL: output error
> * -ENOMEM: output is truncated
> */
> -static int create_modalias(struct acpi_device *acpi_dev, char *modalias,
> - int size)
> +static int create_pnp_modalias(struct acpi_device *acpi_dev, char *modalias,
> + int size)
> {
> int len;
> int count;
> @@ -132,58 +132,74 @@ static int create_modalias(struct acpi_d
> if (list_empty(&acpi_dev->pnp.ids))
> return 0;
>
> + len = snprintf(modalias, size, "acpi:");
> + size -= len;
> +
> + list_for_each_entry(id, &acpi_dev->pnp.ids, list) {
> + if (!strcmp(id->id, "PRP0001"))
> + continue;
> +
> + count = snprintf(&modalias[len], size, "%s:", id->id);
> + if (count < 0)
> + return -EINVAL;
> +
> + if (count >= size)
> + return -ENOMEM;
> +
> + len += count;
> + size -= count;
> + }
> + modalias[len] = '\0';
> + return len;
> +}
> +
> +static int create_of_modalias(struct acpi_device *acpi_dev, char *modalias,
> + int size)
> +{
> + struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
> + const union acpi_object *of_compatible, *obj;
> + int len, count;
> + int i, nval;
> + char *c;
> +
> /*
> - * If the device has PRP0001 we expose DT compatible modalias
> - * instead in form of of:NnameTCcompatible.
> + * If the device has PRP0001 we expose DT compatible modalias as
> + * of:NnameTCcompatible.
> */
> - if (acpi_dev->data.of_compatible) {
> - struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
> - const union acpi_object *of_compatible, *obj;
> - int i, nval;
> - char *c;
> -
> - acpi_get_name(acpi_dev->handle, ACPI_SINGLE_NAME, &buf);
> - /* DT strings are all in lower case */
> - for (c = buf.pointer; *c != '\0'; c++)
> - *c = tolower(*c);
> -
> - len = snprintf(modalias, size, "of:N%sT", (char *)buf.pointer);
> - ACPI_FREE(buf.pointer);
> -
> - of_compatible = acpi_dev->data.of_compatible;
> - if (of_compatible->type == ACPI_TYPE_PACKAGE) {
> - nval = of_compatible->package.count;
> - obj = of_compatible->package.elements;
> - } else { /* Must be ACPI_TYPE_STRING. */
> - nval = 1;
> - obj = of_compatible;
> - }
> - for (i = 0; i < nval; i++, obj++) {
> - count = snprintf(&modalias[len], size, "C%s",
> - obj->string.pointer);
> - if (count < 0)
> - return -EINVAL;
> - if (count >= size)
> - return -ENOMEM;
> + if (!acpi_dev->data.of_compatible)
> + return 0;
>
> - len += count;
> - size -= count;
> - }
> - } else {
> - len = snprintf(modalias, size, "acpi:");
> - size -= len;
> + acpi_get_name(acpi_dev->handle, ACPI_SINGLE_NAME, &buf);
> + /* DT strings are all in lower case */
> + for (c = buf.pointer; *c != '\0'; c++)
> + *c = tolower(*c);
>
> - list_for_each_entry(id, &acpi_dev->pnp.ids, list) {
> - count = snprintf(&modalias[len], size, "%s:", id->id);
> - if (count < 0)
> - return -EINVAL;
> - if (count >= size)
> - return -ENOMEM;
> - len += count;
> - size -= count;
> - }
> + len = snprintf(modalias, size, "of:N%sT", (char *)buf.pointer);
> + ACPI_FREE(buf.pointer);
> +
> + if (len <= 0)
> + return len;
> +
> + of_compatible = acpi_dev->data.of_compatible;
> + if (of_compatible->type == ACPI_TYPE_PACKAGE) {
> + nval = of_compatible->package.count;
> + obj = of_compatible->package.elements;
> + } else { /* Must be ACPI_TYPE_STRING. */
> + nval = 1;
> + obj = of_compatible;
> }
> + for (i = 0; i < nval; i++, obj++) {
> + count = snprintf(&modalias[len], size, "C%s",
> + obj->string.pointer);
> + if (count < 0)
> + return -EINVAL;
> +
> + if (count >= size)
> + return -ENOMEM;
>
> + len += count;
> + size -= count;
> + }
> modalias[len] = '\0';
> return len;
> }
> @@ -236,61 +252,89 @@ static struct acpi_device *acpi_companio
> return adev;
> }
>
> -/*
> - * Creates uevent modalias field for ACPI enumerated devices.
> - * Because the other buses does not support ACPI HIDs & CIDs.
> - * e.g. for a device with hid:IBM0001 and cid:ACPI0001 you get:
> - * "acpi:IBM0001:ACPI0001"
> - */
> -int acpi_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env)
> +int __acpi_device_uevent_modalias(struct acpi_device *adev,
> + struct kobj_uevent_env *env)
> {
> int len;
>
> - if (!acpi_companion_match(dev))
> + if (!adev)
> return -ENODEV;
>
> if (add_uevent_var(env, "MODALIAS="))
> return -ENOMEM;
> - len = create_modalias(ACPI_COMPANION(dev), &env->buf[env->buflen - 1],
> - sizeof(env->buf) - env->buflen);
> - if (len <= 0)
> +
> + len = create_pnp_modalias(adev, &env->buf[env->buflen - 1],
> + sizeof(env->buf) - env->buflen);
> + if (len < 0)
> + return len;
If there is only PRP0001 in the list this will create:
MODALIAS=acpi:
which I think is not correct. Better not to create the entry at all in
that case.
> +
> + env->buflen += len;
> +
> + if (add_uevent_var(env, "MODALIAS="))
> + return -ENOMEM;
> +
> + len = create_of_modalias(adev, &env->buf[env->buflen - 1],
> + sizeof(env->buf) - env->buflen);
> + if (len < 0)
> return len;
> +
> env->buflen += len;
> +
> return 0;
> }
> -EXPORT_SYMBOL_GPL(acpi_device_uevent_modalias);
>
> /*
> - * Creates modalias sysfs attribute for ACPI enumerated devices.
> + * Creates uevent modalias field for ACPI enumerated devices.
> * Because the other buses does not support ACPI HIDs & CIDs.
> * e.g. for a device with hid:IBM0001 and cid:ACPI0001 you get:
> * "acpi:IBM0001:ACPI0001"
> */
> -int acpi_device_modalias(struct device *dev, char *buf, int size)
> +int acpi_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env)
> {
> - int len;
> + return __acpi_device_uevent_modalias(acpi_companion_match(dev), env);
> +}
> +EXPORT_SYMBOL_GPL(acpi_device_uevent_modalias);
> +
> +static int __acpi_device_modalias(struct acpi_device *adev, char *buf, int size)
> +{
> + int len, count;
>
> - if (!acpi_companion_match(dev))
> + if (!adev)
> return -ENODEV;
>
> - len = create_modalias(ACPI_COMPANION(dev), buf, size -1);
> - if (len <= 0)
> + len = create_pnp_modalias(adev, buf, size - 1);
> + if (len < 0) {
> return len;
> - buf[len++] = '\n';
> + } else if (len > 0) {
> + buf[len++] = '\n';
> + size -= len;
> + }
> + count = create_of_modalias(adev, buf, size - 1);
This will overwrite the ACPI modalias as you did not increase buf
itself.
> + if (count < 0) {
> + return count;
> + } else if (count > 0) {
> + len += count;
> + buf[len++] = '\n';
> + }
> +
> return len;
> }
I used patch below on top of this and tried on Minnowboard MAX with two
devices: one with sole PRP0001 entry and one with _HID and _CIDs where
one _CID is PRP0001.
First is the SPI eeprom with only PRP0001 in its _HID:
# cat /sys/bus/spi/devices/spi-PRP0001\:00/modalias
of:Nat25TCatmel,at25
# cat /sys/bus/spi/devices/spi-PRP0001\:00/uevent
DRIVER=at25
MODALIAS=of:Nat25TCatmel,at25
Looks good to me.
Next is an I2C eeprom with following IDs in DSDT:
Device (AT24)
{
Name (_HID, "EEP0024")
Name (_CID, Package () {"PRP0001","ATML2402"})
...
This gives me:
# cat /sys/bus/i2c/devices/i2c-EEP0024\:00/modalias
acpi:EEP0024:ATML2402:
of:Nat24TCatmel,24c02
# cat /sys/bus/i2c/devices/i2c-EEP0024\:00/uevent
DRIVER=at24
MODALIAS=acpi:EEP0024:ATML2402:
MODALIAS=of:Nat24TCatmel,24c02
Also looks okay.
For both devices modprobe/udev is able to load the drivers
automatically:
# lsmod
...
at24 6602 0
at25 5741 0
------8<-------8<--------
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 75697e06aad5..f509ddc29c0c 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -125,13 +125,25 @@ int acpi_scan_add_handler_with_hotplug(struct acpi_scan_handler *handler,
static int create_pnp_modalias(struct acpi_device *acpi_dev, char *modalias,
int size)
{
- int len;
+ int len, nids = 0;
int count;
struct acpi_hardware_id *id;
if (list_empty(&acpi_dev->pnp.ids))
return 0;
+ /*
+ * First check for a sole PRP0001 and in that case do not create
+ * empty ACPI modalias for the device.
+ */
+ nids = 0;
+ list_for_each_entry(id, &acpi_dev->pnp.ids, list) {
+ if (strcmp(id->id, "PRP0001"))
+ nids++;
+ }
+ if (!nids)
+ return 0;
+
len = snprintf(modalias, size, "acpi:");
size -= len;
@@ -268,10 +280,12 @@ int __acpi_device_uevent_modalias(struct acpi_device *adev,
if (len < 0)
return len;
- env->buflen += len;
+ if (len > 0) {
+ env->buflen += len;
- if (add_uevent_var(env, "MODALIAS="))
- return -ENOMEM;
+ if (add_uevent_var(env, "MODALIAS="))
+ return -ENOMEM;
+ }
len = create_of_modalias(adev, &env->buf[env->buflen - 1],
sizeof(env->buf) - env->buflen);
@@ -309,7 +323,7 @@ static int __acpi_device_modalias(struct acpi_device *adev, char *buf, int size)
buf[len++] = '\n';
size -= len;
}
- count = create_of_modalias(adev, buf, size - 1);
+ count = create_of_modalias(adev, buf + len, size - 1);
if (count < 0) {
return count;
} else if (count > 0) {
--
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