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ACPI: bus: Rework the handling of \_SB._OSC platform features 

Both acpi_bus_osc_negotiate_platform_control() and
acpi_bus_osc_negotiate_usb_control() first call acpi_run_osc() to
evaluate _OSC in "query mode", with OSC_QUERY_ENABLE set in the
capabilities buffer, and then use the resultant feature mask as
the input buffer for requesting control of those features by
calling acpi_run_osc() to evaluate _OSC with OSC_QUERY_ENABLE clear.

This involves some code duplication and unnecessary memory
allocations, so introduce a new helper function carrying out an
_OSC handshake along the lines of the above description in a simpler
way and update acpi_bus_osc_negotiate_platform_control() to use it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Link: https://patch.msgid.link/1966378.CQOukoFCf9@rafael.j.wysocki
This commit is contained in:
Rafael J. Wysocki 2025-12-22 20:21:19 +01:00
parent 5ada805104
commit e5322888e6
1 changed files with 101 additions and 40 deletions
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141
drivers/acpi/bus.c
View File

@ -325,6 +325,92 @@ out:
}
EXPORT_SYMBOL(acpi_run_osc);
static int acpi_osc_handshake(acpi_handle handle, const char *uuid_str,
int rev, struct acpi_buffer *cap)
{
union acpi_object in_params[4], *out_obj;
size_t bufsize = cap->length / sizeof(u32);
struct acpi_object_list input;
struct acpi_buffer output;
u32 *capbuf, *retbuf, test;
guid_t guid;
int ret, i;
if (!cap || cap->length < 2 * sizeof(32) || guid_parse(uuid_str, &guid))
return -EINVAL;
/* First evaluate _OSC with OSC_QUERY_ENABLE set. */
capbuf = cap->pointer;
capbuf[OSC_QUERY_DWORD] = OSC_QUERY_ENABLE;
ret = acpi_eval_osc(handle, &guid, rev, cap, in_params, &output);
if (ret)
return ret;
out_obj = output.pointer;
retbuf = (u32 *)out_obj->buffer.pointer;
if (acpi_osc_error_check(handle, &guid, rev, cap, retbuf)) {
ret = -ENODATA;
goto out;
}
/*
* Clear the feature bits in the capabilities buffer that have not been
* acknowledged and clear the return buffer.
*/
for (i = OSC_QUERY_DWORD + 1, test = 0; i < bufsize; i++) {
capbuf[i] &= retbuf[i];
test |= capbuf[i];
retbuf[i] = 0;
}
/*
* If none of the feature bits have been acknowledged, there's nothing
* more to do. capbuf[] contains a feature mask of all zeros.
*/
if (!test)
goto out;
retbuf[OSC_QUERY_DWORD] = 0;
/*
* Now evaluate _OSC again (directly) with OSC_QUERY_ENABLE clear and
* the updated input and output buffers used before. Since the feature
* bits that were clear in the return buffer from the previous _OSC
* evaluation are also clear in the capabilities buffer now, this _OSC
* evaluation is not expected to fail.
*/
capbuf[OSC_QUERY_DWORD] = 0;
/* Reuse in_params[] populated by acpi_eval_osc(). */
input.pointer = in_params;
input.count = 4;
if (ACPI_FAILURE(acpi_evaluate_object(handle, "_OSC", &input, &output))) {
ret = -ENODATA;
goto out;
}
/*
* Clear the feature bits in capbuf[] that have not been acknowledged.
* After that, capbuf[] contains the resultant feature mask.
*/
for (i = OSC_QUERY_DWORD + 1; i < bufsize; i++)
capbuf[i] &= retbuf[i];
if (retbuf[OSC_QUERY_DWORD] & OSC_ERROR_MASK) {
/*
* Complain about the unexpected errors and print diagnostic
* information related to them.
*/
acpi_handle_err(handle, "_OSC: errors while processing control request\n");
acpi_handle_err(handle, "_OSC: some features may be missing\n");
acpi_osc_error_check(handle, &guid, rev, cap, retbuf);
}
out:
ACPI_FREE(out_obj);
return ret;
}
bool osc_sb_apei_support_acked;
/*
@ -356,19 +442,16 @@ EXPORT_SYMBOL_GPL(osc_sb_native_usb4_support_confirmed);
bool osc_sb_cppc2_support_acked;
static u8 sb_uuid_str[] = "0811B06E-4A27-44F9-8D60-3CBBC22E7B48";
static void acpi_bus_osc_negotiate_platform_control(void)
{
u32 capbuf[2], *capbuf_ret;
struct acpi_osc_context context = {
.uuid_str = sb_uuid_str,
.rev = 1,
.cap.length = 8,
.cap.pointer = capbuf,
static const u8 sb_uuid_str[] = "0811B06E-4A27-44F9-8D60-3CBBC22E7B48";
u32 capbuf[2];
struct acpi_buffer cap = {
.pointer = capbuf,
.length = sizeof(capbuf),
};
acpi_handle handle;
capbuf[OSC_QUERY_DWORD] = OSC_QUERY_ENABLE;
capbuf[OSC_SUPPORT_DWORD] = OSC_SB_PR3_SUPPORT; /* _PR3 is in use */
if (IS_ENABLED(CONFIG_ACPI_PROCESSOR_AGGREGATOR))
capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PAD_SUPPORT;
@ -414,43 +497,21 @@ static void acpi_bus_osc_negotiate_platform_control(void)
if (ACPI_FAILURE(acpi_get_handle(NULL, "\\_SB", &handle)))
return;
if (ACPI_FAILURE(acpi_run_osc(handle, &context)))
if (acpi_osc_handshake(handle, sb_uuid_str, 1, &cap))
return;
capbuf_ret = context.ret.pointer;
if (context.ret.length <= OSC_SUPPORT_DWORD) {
kfree(context.ret.pointer);
return;
}
/*
* Now run _OSC again with query flag clear and with the caps
* supported by both the OS and the platform.
*/
capbuf[OSC_QUERY_DWORD] = 0;
capbuf[OSC_SUPPORT_DWORD] = capbuf_ret[OSC_SUPPORT_DWORD];
kfree(context.ret.pointer);
if (ACPI_FAILURE(acpi_run_osc(handle, &context)))
return;
capbuf_ret = context.ret.pointer;
if (context.ret.length > OSC_SUPPORT_DWORD) {
#ifdef CONFIG_ACPI_CPPC_LIB
osc_sb_cppc2_support_acked = capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_CPCV2_SUPPORT;
osc_sb_cppc2_support_acked = capbuf[OSC_SUPPORT_DWORD] & OSC_SB_CPCV2_SUPPORT;
#endif
osc_sb_apei_support_acked =
capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_APEI_SUPPORT;
osc_pc_lpi_support_confirmed =
capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_PCLPI_SUPPORT;
osc_sb_native_usb4_support_confirmed =
capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_NATIVE_USB4_SUPPORT;
osc_cpc_flexible_adr_space_confirmed =
capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_CPC_FLEXIBLE_ADR_SPACE;
}
kfree(context.ret.pointer);
osc_sb_apei_support_acked =
capbuf[OSC_SUPPORT_DWORD] & OSC_SB_APEI_SUPPORT;
osc_pc_lpi_support_confirmed =
capbuf[OSC_SUPPORT_DWORD] & OSC_SB_PCLPI_SUPPORT;
osc_sb_native_usb4_support_confirmed =
capbuf[OSC_SUPPORT_DWORD] & OSC_SB_NATIVE_USB4_SUPPORT;
osc_cpc_flexible_adr_space_confirmed =
capbuf[OSC_SUPPORT_DWORD] & OSC_SB_CPC_FLEXIBLE_ADR_SPACE;
}
/*