kernel/linux.git/drivers/cpufreq/amd-pstate.c, branch v6.3

amd-pstate: Fix amd_pstate mode switch

2023-04-11T18:44:25+00:00

amd_pstate mode can be changed by writing the mode name to the `status` sysfs. But some combinations are not working. Fix this issue by taking care of the edge cases. Before the fix the mode change combination test fails: #./pst_test.sh Test passed: from: disable, to Test passed: from: disable, to disable Test failed: 1, From mode: disable, to mode: passive Test failed: 1, From mode: disable, to mode: active Test failed: 1, From mode: passive, to mode: active Test passed: from: passive, to disable Test failed: 1, From mode: passive, to mode: passive Test failed: 1, From mode: passive, to mode: active Test failed: 1, From mode: active, to mode: active Test passed: from: active, to disable Test failed: 1, From mode: active, to mode: passive Test failed: 1, From mode: active, to mode: active After the fix test passes: #./pst_test.sh Test passed: from: disable, to Test passed: from: disable, to disable Test passed: from: disable, to passive Test passed: from: disable, to active Test passed: from: passive, to active Test passed: from: passive, to disable Test passed: from: passive, to passive Test passed: from: passive, to active Test passed: from: active, to active Test passed: from: active, to disable Test passed: from: active, to passive Test passed: from: active, to active Fixes: abd61c08ef349 ("cpufreq: amd-pstate: add driver working mode switch support") Acked-by: Huang Rui Reviewed-by: Alexey Kardashevskiy Signed-off-by: Wyes Karny Signed-off-by: Rafael J. Wysocki

cpufreq: amd-pstate: remove MODULE_LICENSE in non-modules

2023-02-23T19:01:23+00:00

Since commit 8b41fc4454e ("kbuild: create modules.builtin without Makefile.modbuiltin or tristate.conf"), MODULE_LICENSE declarations are used to identify modules. As a consequence, uses of the macro in non-modules will cause modprobe to misidentify their containing object file as a module when it is not (false positives), and modprobe might succeed rather than failing with a suitable error message. So remove it in amd-pstate.c which cannot be built as a module. Signed-off-by: Nick Alcock Suggested-by: Luis Chamberlain [ rjw: Subject and changelog adjustments ] Signed-off-by: Rafael J. Wysocki

cpufreq: amd-pstate: Let user know amd-pstate is disabled

2023-02-23T18:56:08+00:00

Commit 202e683df37c ("cpufreq: amd-pstate: add amd-pstate driver parameter for mode selection") changed the driver to be disabled by default, and this can surprise users. Let users know what happened so they can decide what to do next. Link: https://bugs.launchpad.net/bugs/2006942 Signed-off-by: Kai-Heng Feng Acked-by: Huang Rui Reviewed-by: Yuan Perry Signed-off-by: Rafael J. Wysocki

cpufreq: amd-pstate: Fix invalid write to MSR_AMD_CPPC_REQ

2023-02-15T14:58:07+00:00

`amd_pstate_set_epp` function uses `cppc_req_cached` and `epp` variable to update the MSR_AMD_CPPC_REQ register for AMD MSR systems. The recent commit 7cca9a9851a5 ("cpufreq: amd-pstate: avoid uninitialized variable use") changed the sequence of updating cppc_req_cached and writing the MSR_AMD_CPPC_REQ. Therefore while switching from powersave to performance governor and vice-versa in active mode MSR_AMD_CPPC_REQ is set with the previous cached value. To fix this: first update the `cppc_req_cached` variable and then call `amd_pstate_set_epp` function. - Before commit 7cca9a9851a5 ("cpufreq: amd-pstate: avoid uninitialized variable use"): With powersave governor: [ 1.652743] amd_pstate_epp_init: writing to cppc_req_cached = 0x1eff [ 1.652744] amd_pstate_set_epp: writing cppc_req_cached = 0x1eff [ 1.652746] amd_pstate_set_epp: writing min_perf = 30, des_perf = 0, max_perf = 255, epp = 0 Changing to performance governor: [ 300.493842] amd_pstate_epp_init: writing to cppc_req_cached = 0xffff [ 300.493846] amd_pstate_set_epp: writing cppc_req_cached = 0xffff [ 300.493847] amd_pstate_set_epp: writing min_perf = 255, des_perf = 0, max_perf = 255, epp = 0 - After commit 7cca9a9851a5 ("cpufreq: amd-pstate: avoid uninitialized variable use"): With powersave governor: [ 1.646037] amd_pstate_set_epp: writing cppc_req_cached = 0xffff [ 1.646038] amd_pstate_set_epp: writing min_perf = 255, des_perf = 0, max_perf = 255, epp = 0 [ 1.646042] amd_pstate_epp_init: writing to cppc_req_cached = 0x1eff Changing to performance governor: [ 687.117401] amd_pstate_set_epp: writing cppc_req_cached = 0x1eff [ 687.117405] amd_pstate_set_epp: writing min_perf = 30, des_perf = 0, max_perf = 255, epp = 0 [ 687.117419] amd_pstate_epp_init: writing to cppc_req_cached = 0xffff - After this fix: With powersave governor: [ 2.525717] amd_pstate_epp_init: writing to cppc_req_cached = 0x1eff [ 2.525720] amd_pstate_set_epp: writing cppc_req_cached = 0x1eff [ 2.525722] amd_pstate_set_epp: writing min_perf = 30, des_perf = 0, max_perf = 255, epp = 0 Changing to performance governor: [ 3440.152468] amd_pstate_epp_init: writing to cppc_req_cached = 0xffff [ 3440.152473] amd_pstate_set_epp: writing cppc_req_cached = 0xffff [ 3440.152474] amd_pstate_set_epp: writing min_perf = 255, des_perf = 0, max_perf = 255, epp = 0 Fixes: 7cca9a9851a5 ("cpufreq: amd-pstate: avoid uninitialized variable use") Signed-off-by: Wyes Karny Acked-by: Huang Rui Signed-off-by: Rafael J. Wysocki

cpufreq: amd-pstate: avoid uninitialized variable use

2023-02-09T19:21:42+00:00

The new epp support causes warnings about three separate but related bugs: 1) failing before allocation should just return an error: drivers/cpufreq/amd-pstate.c:951:6: error: variable 'ret' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] if (!dev) ^~~~ drivers/cpufreq/amd-pstate.c:1018:9: note: uninitialized use occurs here return ret; ^~~ 2) wrong variable to store return code: drivers/cpufreq/amd-pstate.c:963:6: error: variable 'ret' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] if (rc) ^~ drivers/cpufreq/amd-pstate.c:1019:9: note: uninitialized use occurs here return ret; ^~~ drivers/cpufreq/amd-pstate.c:963:2: note: remove the 'if' if its condition is always false if (rc) ^~~~~~~ 3) calling amd_pstate_set_epp() in cleanup path after determining that it should not be called: drivers/cpufreq/amd-pstate.c:1055:6: error: variable 'epp' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] if (cpudata->epp_policy == cpudata->policy) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/cpufreq/amd-pstate.c:1080:30: note: uninitialized use occurs here amd_pstate_set_epp(cpudata, epp); ^~~ All three are trivial to fix, but most likely there are additional bugs in this function when the error handling was not really tested. Fixes: ffa5096a7c33 ("cpufreq: amd-pstate: implement Pstate EPP support for the AMD processors") Signed-off-by: Arnd Bergmann Tested-by: Wyes Karny Reviewed-by: Yuan Perry Acked-by: Huang Rui Signed-off-by: Rafael J. Wysocki

cpufreq: Make cpufreq_unregister_driver() return void

2023-02-09T19:19:18+00:00

All but a few drivers ignore the return value of cpufreq_unregister_driver(). Those few that don't only call it after cpufreq_register_driver() succeeded, in which case the call doesn't fail. Make the function return no value and add a WARN_ON for the case that the function is called in an invalid situation (i.e. without a previous successful call to cpufreq_register_driver()). Signed-off-by: Uwe Kleine-König Acked-by: Florian Fainelli # brcmstb-avs-cpufreq.c Acked-by: Viresh Kumar Reviewed-by: AngeloGioacchino Del Regno Signed-off-by: Rafael J. Wysocki

cpufreq: amd-pstate: convert sprintf with sysfs_emit()

2023-02-03T20:59:42+00:00

replace the sprintf with a more generic sysfs_emit function No intended potential function impact Acked-by: Huang Rui Reviewed-by: Mario Limonciello Reviewed-by: Wyes Karny Tested-by: Wyes Karny Signed-off-by: Perry Yuan Signed-off-by: Rafael J. Wysocki

cpufreq: amd-pstate: add driver working mode switch support

2023-02-03T20:59:42+00:00

While amd-pstate driver was loaded with specific driver mode, it will need to check which mode is enabled for the pstate driver,add this sysfs entry to show the current status $ cat /sys/devices/system/cpu/amd-pstate/status active Meanwhile, user can switch the pstate driver mode with writing mode string to sysfs entry as below. Enable passive mode: $ sudo bash -c "echo passive > /sys/devices/system/cpu/amd-pstate/status" Enable active mode (EPP driver mode): $ sudo bash -c "echo active > /sys/devices/system/cpu/amd-pstate/status" Acked-by: Huang Rui Reviewed-by: Mario Limonciello Reviewed-by: Wyes Karny Tested-by: Wyes Karny Signed-off-by: Perry Yuan Signed-off-by: Rafael J. Wysocki

cpufreq: amd-pstate: implement suspend and resume callbacks

2023-02-03T20:59:42+00:00

add suspend and resume support for the AMD processors by amd_pstate_epp driver instance. When the CPPC is suspended, EPP driver will set EPP profile to 'power' profile and set max/min perf to lowest perf value. When resume happens, it will restore the MSR registers with previous cached value. Acked-by: Huang Rui Reviewed-by: Mario Limonciello Reviewed-by: Wyes Karny Tested-by: Wyes Karny Signed-off-by: Perry Yuan Signed-off-by: Rafael J. Wysocki

cpufreq: amd-pstate: implement amd pstate cpu online and offline callback

2023-02-03T20:59:41+00:00

Adds online and offline driver callback support to allow cpu cores go offline and help to restore the previous working states when core goes back online later for EPP driver mode. Acked-by: Huang Rui Reviewed-by: Mario Limonciello Reviewed-by: Wyes Karny Tested-by: Wyes Karny Signed-off-by: Perry Yuan Signed-off-by: Rafael J. Wysocki