On Thursday, May 14, 2015 10:36:52 PM Rafael J. Wysocki wrote:
On Thursday, May 14, 2015 03:31:26 PM Dominik Brodowski wrote:
By using a module parameter named acpi.supported_rev=<value>, the BIOS may be told a different supported ACPI revision compared to the default (which currently is 5, but will be modified to 2 when the revert of b1ef29725865 is reverted).
Signed-off-by: Dominik Brodowski linux@dominikbrodowski.net
Documentation/kernel-parameters.txt | 14 ++++++++++++++ drivers/acpi/osl.c | 16 ++++++++++++++++ 2 files changed, 30 insertions(+)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 61ab162..75f1f8e 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -335,6 +335,20 @@ bytes respectively. Such letter suffixes can also be entirely omitted. to assume that this machine's pmtimer latches its value and always returns good values.
- acpi.rev= [HW,ACPI]
Tell ACPI BIOS the supported ACPI REVFormat: <int> in range 0..5Up to and including Linux v4.1, the BIOS was told whichACPI revision the ACPICA subsystem in Linux actuallysupports (which was 5 at the time); from v4.2 on, thisvalue will be set statically to 2 to match the behaviorof other ACPI implementations. As some BIOS may operatedifferently depending on which value _REV is set to, thisparameter offers the capability to specify what to exportto the BIOS. Note that such changes in the behavior ofthe BIOS may only be visible after cold booting thesystem with this parameter _twice_.- acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode Format: { level | edge | high | low }
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c index db14a66..caa52f7 100644 --- a/drivers/acpi/osl.c +++ b/drivers/acpi/osl.c @@ -538,6 +538,11 @@ acpi_os_get_physical_address(void *virt, acpi_physical_address * phys)
static char acpi_os_name[ACPI_MAX_OVERRIDE_LEN];
+/* acpi_supported_rev is 0 in case of no override; overrides are limited to
- values between 1 to 5. To simplify casting, use an unsigned long */
+static unsigned long acpi_supported_rev; +module_param_named(rev, acpi_supported_rev, ulong, 0);
acpi_status acpi_os_predefined_override(const struct acpi_predefined_names *init_val, char **new_val) @@ -552,6 +557,17 @@ acpi_os_predefined_override(const struct acpi_predefined_names *init_val, *new_val = acpi_os_name; }
- if (!memcmp(init_val->name, "_REV", 4) && (acpi_supported_rev > 0)) {
if (acpi_supported_rev <= 5) {So the only value that would really make sense here is 5.
1 should never ever be used with Linux, 2 is the default, 3 is equivalent to 5 for all practical purposes and 4 has never been used in practice, so it is meaningless.
I'd be better to rename the command line switch to acpi.rev_override and simply do "acpi_supported_rev = 5" for it as well as in acpi_set_supported_rev() in [3/4].
printk(KERN_INFO PREFIX"Overriding _REV definition to %lu\n",acpi_supported_rev);*new_val = (char *) acpi_supported_rev;} elseprintk(KERN_INFO PREFIX"_REV override must be between 1 to 5");- }
- return AE_OK;
}
Overall, what about the appended patch instead of your [2-3/4] (modulo the new command line parameter description which is missing here ATM)?
--- drivers/acpi/Kconfig | 22 ++++++++++++++++++++++ drivers/acpi/blacklist.c | 26 ++++++++++++++++++++++++++ drivers/acpi/internal.h | 4 ++++ drivers/acpi/osl.c | 18 ++++++++++++++++++ 4 files changed, 70 insertions(+)
Index: linux-pm/drivers/acpi/blacklist.c =================================================================== --- linux-pm.orig/drivers/acpi/blacklist.c +++ linux-pm/drivers/acpi/blacklist.c @@ -162,6 +162,15 @@ static int __init dmi_disable_osi_win8(c acpi_osi_setup("!Windows 2012"); return 0; } +#ifdef CONFIG_ACPI_REV_OVERRIDE_POSSIBLE +static int __init dmi_enable_rev_override(const struct dmi_system_id *d) +{ + printk(KERN_NOTICE PREFIX "DMI detected: %s (force ACPI _REV to 5)\n", + d->ident); + acpi_rev_override_setup(NULL); + return 0; +} +#endif
static struct dmi_system_id acpi_osi_dmi_table[] __initdata = { { @@ -325,6 +334,23 @@ static struct dmi_system_id acpi_osi_dmi DMI_MATCH(DMI_PRODUCT_NAME, "1015PX"), }, }, + +#ifdef CONFIG_ACPI_REV_OVERRIDE_POSSIBLE + /* + * DELL XPS 13 (2015) switches sound between HDA and I2S + * depending on the ACPI _REV callback. If userspace supports + * I2S sufficiently (or if you do not care about sound), you + * can safely disable this quirk. + */ + { + .callback = dmi_enable_rev_override, + .ident = "DELL XPS 13 (2015)", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "XPS 13 9343"), + }, + }, +#endif {} };
Index: linux-pm/drivers/acpi/internal.h =================================================================== --- linux-pm.orig/drivers/acpi/internal.h +++ linux-pm/drivers/acpi/internal.h @@ -23,6 +23,10 @@
#define PREFIX "ACPI: "
+#ifdef CONFIG_ACPI_REV_OVERRIDE_POSSIBLE +int __init acpi_rev_override_setup(char *str); +#endif + acpi_status acpi_os_initialize1(void); int init_acpi_device_notify(void); int acpi_scan_init(void); Index: linux-pm/drivers/acpi/osl.c =================================================================== --- linux-pm.orig/drivers/acpi/osl.c +++ linux-pm/drivers/acpi/osl.c @@ -534,6 +534,19 @@ acpi_os_get_physical_address(void *virt, } #endif
+#ifdef CONFIG_ACPI_REV_OVERRIDE_POSSIBLE +static bool acpi_rev_override; + +int __init acpi_rev_override_setup(char *str) +{ + acpi_rev_override = true; + return 1; +} +__setup("acpi_rev_override", acpi_rev_override_setup); +#else +#define acpi_rev_override false +#endif + #define ACPI_MAX_OVERRIDE_LEN 100
static char acpi_os_name[ACPI_MAX_OVERRIDE_LEN]; @@ -552,6 +565,11 @@ acpi_os_predefined_override(const struct *new_val = acpi_os_name; }
+ if (!memcmp(init_val->name, "_REV", 4) && acpi_rev_override) { + printk(KERN_INFO PREFIX "Overriding _REV return value to 5\n"); + *new_val = (char *)5; + } + return AE_OK; }
Index: linux-pm/drivers/acpi/Kconfig =================================================================== --- linux-pm.orig/drivers/acpi/Kconfig +++ linux-pm/drivers/acpi/Kconfig @@ -428,6 +428,28 @@ config XPOWER_PMIC_OPREGION help This config adds ACPI operation region support for XPower AXP288 PMIC.
++config ACPI_REV_OVERRIDE_POSSIBLE + bool "Allow supported ACPI revision to be overriden" + depends on X86 + default y + help + The platform firmware on some systems expects Linux to return "5" as + the supported ACPI revision which makes it expose system configuration + information in a special way. + + For example, based on what ACPI exports as the supported revision, + Dell XPS 13 (2015) configures its audio device to either work in HDA + mode or in I2S mode, where the former is supposed to be used on Linux + until the latter is fully supported (in the kernel as well as in user + space). + + This option enables a DMI-based quirk for the above Dell machine (so + that HDA audio is exposed by the platform firmware to the kernel) and + makes it possible to force the kernel to return "5" as the supported + ACPI revision via the "acpi_rev_override" command line switch (when + using that switch it may be necessary to carry out a cold reboot + _twice_ in a row to make it take effect on the firmware). + endif
endif # ACPI