<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/drivers/cpufreq, branch v6.1</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>cpufreq: amd-pstate: add amd-pstate driver parameter for mode selection</title>
<updated>2022-11-22T18:57:15+00:00</updated>
<author>
<name>Perry Yuan</name>
<email>Perry.Yuan@amd.com</email>
</author>
<published>2022-11-17T07:35:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=202e683df37cdf4c38e06e56ac91cc170ef49058'/>
<id>202e683df37cdf4c38e06e56ac91cc170ef49058</id>
<content type='text'>
When the amd_pstate driver is built-in users still need a method to be
able enable or disable it depending upon their circumstance.
Add support for an early parameter to do this.

There is some performance degradation on a number of ASICs in the
passive mode. This performance issue was originally discovered in
shared memory systems but it has been proven that certain workloads
on MSR systems also suffer performance issues.
Set the amd-pstate driver as disabled by default to temporarily
mitigate the performance problem.

 1) with `amd_pstate=disable`, pstate driver will be disabled to load at
    kernel booting.

 2) with `amd_pstate=passive`, pstate driver will be enabled and loaded
    as non-autonomous working mode supported in the low-level power
    management firmware.

 3) If neither parameter is specified, the driver will be disabled by
    default to avoid triggering performance regressions in certain ASICs

Acked-by: Huang Rui &lt;ray.huang@amd.com&gt;
Reviewed-by: Gautham R. Shenoy &lt;gautham.shenoy@amd.com&gt;
Tested-by: Wyes Karny &lt;wyes.karny@amd.com&gt;
Signed-off-by: Perry Yuan &lt;Perry.Yuan@amd.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When the amd_pstate driver is built-in users still need a method to be
able enable or disable it depending upon their circumstance.
Add support for an early parameter to do this.

There is some performance degradation on a number of ASICs in the
passive mode. This performance issue was originally discovered in
shared memory systems but it has been proven that certain workloads
on MSR systems also suffer performance issues.
Set the amd-pstate driver as disabled by default to temporarily
mitigate the performance problem.

 1) with `amd_pstate=disable`, pstate driver will be disabled to load at
    kernel booting.

 2) with `amd_pstate=passive`, pstate driver will be enabled and loaded
    as non-autonomous working mode supported in the low-level power
    management firmware.

 3) If neither parameter is specified, the driver will be disabled by
    default to avoid triggering performance regressions in certain ASICs

Acked-by: Huang Rui &lt;ray.huang@amd.com&gt;
Reviewed-by: Gautham R. Shenoy &lt;gautham.shenoy@amd.com&gt;
Tested-by: Wyes Karny &lt;wyes.karny@amd.com&gt;
Signed-off-by: Perry Yuan &lt;Perry.Yuan@amd.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: amd-pstate: change amd-pstate driver to be built-in type</title>
<updated>2022-11-22T18:57:15+00:00</updated>
<author>
<name>Perry Yuan</name>
<email>Perry.Yuan@amd.com</email>
</author>
<published>2022-11-17T07:35:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=456ca88d8a5258fc66edc42a10053ac8473de2b1'/>
<id>456ca88d8a5258fc66edc42a10053ac8473de2b1</id>
<content type='text'>
Currently when the amd-pstate and acpi_cpufreq are both built into
kernel as module driver, amd-pstate will not be loaded by default
in this case.

Change amd-pstate driver as built-in type, it will resolve the loading
sequence problem to allow user to make amd-pstate driver as the default
cpufreq scaling driver.

Acked-by: Huang Rui &lt;ray.huang@amd.com&gt;
Reviewed-by: Gautham R. Shenoy &lt;gautham.shenoy@amd.com&gt;
Tested-by: Wyes Karny &lt;wyes.karny@amd.com&gt;
Signed-off-by: Perry Yuan &lt;Perry.Yuan@amd.com&gt;
Fixes: ec437d71db77 ("cpufreq: amd-pstate: Introduce a new AMD P-State driver to support future processors")
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently when the amd-pstate and acpi_cpufreq are both built into
kernel as module driver, amd-pstate will not be loaded by default
in this case.

Change amd-pstate driver as built-in type, it will resolve the loading
sequence problem to allow user to make amd-pstate driver as the default
cpufreq scaling driver.

Acked-by: Huang Rui &lt;ray.huang@amd.com&gt;
Reviewed-by: Gautham R. Shenoy &lt;gautham.shenoy@amd.com&gt;
Tested-by: Wyes Karny &lt;wyes.karny@amd.com&gt;
Signed-off-by: Perry Yuan &lt;Perry.Yuan@amd.com&gt;
Fixes: ec437d71db77 ("cpufreq: amd-pstate: Introduce a new AMD P-State driver to support future processors")
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: amd-pstate: cpufreq: amd-pstate: reset MSR_AMD_PERF_CTL register at init</title>
<updated>2022-11-22T18:57:14+00:00</updated>
<author>
<name>Wyes Karny</name>
<email>wyes.karny@amd.com</email>
</author>
<published>2022-11-17T07:35:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=919f4557696939625085435ebde09a539de2349c'/>
<id>919f4557696939625085435ebde09a539de2349c</id>
<content type='text'>
MSR_AMD_PERF_CTL is guaranteed to be 0 on a cold boot. However, on a
kexec boot, for instance, it may have a non-zero value (if the cpu was
in a non-P0 Pstate).  In such cases, the cores with non-P0 Pstates at
boot will never be pushed to P0, let alone boost frequencies.

Kexec is a common workflow for reboot on Linux and this creates a
regression in performance. Fix it by explicitly setting the
MSR_AMD_PERF_CTL to 0 during amd_pstate driver init.

Cc: All applicable &lt;stable@vger.kernel.org&gt;
Acked-by: Huang Rui &lt;ray.huang@amd.com&gt;
Reviewed-by: Gautham R. Shenoy &lt;gautham.shenoy@amd.com&gt;
Tested-by: Wyes Karny &lt;wyes.karny@amd.com&gt;
Signed-off-by: Wyes Karny &lt;wyes.karny@amd.com&gt;
Signed-off-by: Perry Yuan &lt;Perry.Yuan@amd.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
MSR_AMD_PERF_CTL is guaranteed to be 0 on a cold boot. However, on a
kexec boot, for instance, it may have a non-zero value (if the cpu was
in a non-P0 Pstate).  In such cases, the cores with non-P0 Pstates at
boot will never be pushed to P0, let alone boost frequencies.

Kexec is a common workflow for reboot on Linux and this creates a
regression in performance. Fix it by explicitly setting the
MSR_AMD_PERF_CTL to 0 during amd_pstate driver init.

Cc: All applicable &lt;stable@vger.kernel.org&gt;
Acked-by: Huang Rui &lt;ray.huang@amd.com&gt;
Reviewed-by: Gautham R. Shenoy &lt;gautham.shenoy@amd.com&gt;
Tested-by: Wyes Karny &lt;wyes.karny@amd.com&gt;
Signed-off-by: Wyes Karny &lt;wyes.karny@amd.com&gt;
Signed-off-by: Perry Yuan &lt;Perry.Yuan@amd.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: intel_pstate: hybrid: Use known scaling factor for P-cores</title>
<updated>2022-10-25T13:09:23+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2022-10-24T19:22:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f5c8cf2a4992dd929fa0c2f25c09ee69b8dcbce1'/>
<id>f5c8cf2a4992dd929fa0c2f25c09ee69b8dcbce1</id>
<content type='text'>
Commit 46573fd6369f ("cpufreq: intel_pstate: hybrid: Rework HWP
calibration") attempted to use the information from CPPC (the nominal
performance in particular) to obtain the scaling factor allowing the
frequency to be computed if the HWP performance level of the given CPU
is known or vice versa.

However, it turns out that on some platforms this doesn't work, because
the CPPC information on them does not align with the contents of the
MSR_HWP_CAPABILITIES registers.

This basically means that the only way to make intel_pstate work on all
of the hybrid platforms to date is to use the observation that on all
of them the scaling factor between the HWP performance levels and
frequency for P-cores is 78741 (approximately 100000/1.27).  For
E-cores it is 100000, which is the same as for all of the non-hybrid
"core" platforms and does not require any changes.

Accordingly, make intel_pstate use 78741 as the scaling factor between
HWP performance levels and frequency for P-cores on all hybrid platforms
and drop the dependency of the HWP calibration code on CPPC.

Fixes: 46573fd6369f ("cpufreq: intel_pstate: hybrid: Rework HWP calibration")
Reported-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Acked-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Tested-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Cc: 5.15+ &lt;stable@vger.kernel.org&gt; # 5.15+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 46573fd6369f ("cpufreq: intel_pstate: hybrid: Rework HWP
calibration") attempted to use the information from CPPC (the nominal
performance in particular) to obtain the scaling factor allowing the
frequency to be computed if the HWP performance level of the given CPU
is known or vice versa.

However, it turns out that on some platforms this doesn't work, because
the CPPC information on them does not align with the contents of the
MSR_HWP_CAPABILITIES registers.

This basically means that the only way to make intel_pstate work on all
of the hybrid platforms to date is to use the observation that on all
of them the scaling factor between the HWP performance levels and
frequency for P-cores is 78741 (approximately 100000/1.27).  For
E-cores it is 100000, which is the same as for all of the non-hybrid
"core" platforms and does not require any changes.

Accordingly, make intel_pstate use 78741 as the scaling factor between
HWP performance levels and frequency for P-cores on all hybrid platforms
and drop the dependency of the HWP calibration code on CPPC.

Fixes: 46573fd6369f ("cpufreq: intel_pstate: hybrid: Rework HWP calibration")
Reported-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Acked-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Tested-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Cc: 5.15+ &lt;stable@vger.kernel.org&gt; # 5.15+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: intel_pstate: Read all MSRs on the target CPU</title>
<updated>2022-10-25T13:09:23+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2022-10-24T19:21:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8dbab94d45fb1094cefac7956b7fb987a36e2b12'/>
<id>8dbab94d45fb1094cefac7956b7fb987a36e2b12</id>
<content type='text'>
Some of the MSR accesses in intel_pstate are carried out on the CPU
that is running the code, but the values coming from them are used
for the performance scaling of the other CPUs.

This is problematic, for example, on hybrid platforms where
MSR_TURBO_RATIO_LIMIT for P-cores and E-cores is different, so the
values read from it on a P-core are generally not applicable to E-cores
and the other way around.

For this reason, make the driver access all MSRs on the target CPU on
platforms using the "core" pstate_funcs callbacks which is the case for
all of the hybrid platforms released to date.  For this purpose, pass
a CPU argument to the -&gt;get_max(), -&gt;get_max_physical(), -&gt;get_min()
and -&gt;get_turbo() pstate_funcs callbacks and from there pass it to
rdmsrl_on_cpu() or rdmsrl_safe_on_cpu() to access the MSR on the target
CPU.

Fixes: 46573fd6369f ("cpufreq: intel_pstate: hybrid: Rework HWP calibration")
Acked-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Tested-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Cc: 5.15+ &lt;stable@vger.kernel.org&gt; # 5.15+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Some of the MSR accesses in intel_pstate are carried out on the CPU
that is running the code, but the values coming from them are used
for the performance scaling of the other CPUs.

This is problematic, for example, on hybrid platforms where
MSR_TURBO_RATIO_LIMIT for P-cores and E-cores is different, so the
values read from it on a P-core are generally not applicable to E-cores
and the other way around.

For this reason, make the driver access all MSRs on the target CPU on
platforms using the "core" pstate_funcs callbacks which is the case for
all of the hybrid platforms released to date.  For this purpose, pass
a CPU argument to the -&gt;get_max(), -&gt;get_max_physical(), -&gt;get_min()
and -&gt;get_turbo() pstate_funcs callbacks and from there pass it to
rdmsrl_on_cpu() or rdmsrl_safe_on_cpu() to access the MSR on the target
CPU.

Fixes: 46573fd6369f ("cpufreq: intel_pstate: hybrid: Rework HWP calibration")
Acked-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Tested-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Cc: 5.15+ &lt;stable@vger.kernel.org&gt; # 5.15+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: sun50i: Switch to use dev_err_probe() helper</title>
<updated>2022-10-18T10:52:26+00:00</updated>
<author>
<name>Yang Yingliang</name>
<email>yangyingliang@huawei.com</email>
</author>
<published>2022-09-27T15:40:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=889a50aedcd216cc5f2b98bb2412f0498d417721'/>
<id>889a50aedcd216cc5f2b98bb2412f0498d417721</id>
<content type='text'>
In the probe path, convert pr_err() to dev_err_probe() which will
check if error code is -EPROBE_DEFER and prints the error name.
It also sets the defer probe reason which can be checked later
through debugfs. It's more simple in error path.

Signed-off-by: Yang Yingliang &lt;yangyingliang@huawei.com&gt;
Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In the probe path, convert pr_err() to dev_err_probe() which will
check if error code is -EPROBE_DEFER and prints the error name.
It also sets the defer probe reason which can be checked later
through debugfs. It's more simple in error path.

Signed-off-by: Yang Yingliang &lt;yangyingliang@huawei.com&gt;
Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: qcom-nvmem: Switch to use dev_err_probe() helper</title>
<updated>2022-10-18T10:52:26+00:00</updated>
<author>
<name>Yang Yingliang</name>
<email>yangyingliang@huawei.com</email>
</author>
<published>2022-09-27T15:40:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d78be404f97fadacd6a0d0928e6933e89e1869f6'/>
<id>d78be404f97fadacd6a0d0928e6933e89e1869f6</id>
<content type='text'>
In the probe path, dev_err() can be replaced with dev_err_probe()
which will check if error code is -EPROBE_DEFER and prints the
error name. It also sets the defer probe reason which can be
checked later through debugfs. It's more simple in error path.

Signed-off-by: Yang Yingliang &lt;yangyingliang@huawei.com&gt;
Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In the probe path, dev_err() can be replaced with dev_err_probe()
which will check if error code is -EPROBE_DEFER and prints the
error name. It also sets the defer probe reason which can be
checked later through debugfs. It's more simple in error path.

Signed-off-by: Yang Yingliang &lt;yangyingliang@huawei.com&gt;
Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: imx6q: Switch to use dev_err_probe() helper</title>
<updated>2022-10-18T10:52:25+00:00</updated>
<author>
<name>Yang Yingliang</name>
<email>yangyingliang@huawei.com</email>
</author>
<published>2022-09-27T15:40:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ab4fdc735daf483c70fc7e4b6c49fa8c1999f741'/>
<id>ab4fdc735daf483c70fc7e4b6c49fa8c1999f741</id>
<content type='text'>
In the probe path, dev_err() can be replaced with dev_err_probe()
which will check if error code is -EPROBE_DEFER and prints the
error name. It also sets the defer probe reason which can be
checked later through debugfs. It's more simple in error path.

Signed-off-by: Yang Yingliang &lt;yangyingliang@huawei.com&gt;
Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In the probe path, dev_err() can be replaced with dev_err_probe()
which will check if error code is -EPROBE_DEFER and prints the
error name. It also sets the defer probe reason which can be
checked later through debugfs. It's more simple in error path.

Signed-off-by: Yang Yingliang &lt;yangyingliang@huawei.com&gt;
Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: dt: Switch to use dev_err_probe() helper</title>
<updated>2022-10-18T10:52:25+00:00</updated>
<author>
<name>Yang Yingliang</name>
<email>yangyingliang@huawei.com</email>
</author>
<published>2022-09-27T15:40:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2a808b9f701ba935a67be58a3afa2e3b230cee85'/>
<id>2a808b9f701ba935a67be58a3afa2e3b230cee85</id>
<content type='text'>
In the probe path, dev_err() can be replaced with dev_err_probe()
which will check if error code is -EPROBE_DEFER and prints the
error name. It also sets the defer probe reason which can be
checked later through debugfs. It's more simple in error path.

Signed-off-by: Yang Yingliang &lt;yangyingliang@huawei.com&gt;
Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In the probe path, dev_err() can be replaced with dev_err_probe()
which will check if error code is -EPROBE_DEFER and prints the
error name. It also sets the defer probe reason which can be
checked later through debugfs. It's more simple in error path.

Signed-off-by: Yang Yingliang &lt;yangyingliang@huawei.com&gt;
Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: qcom: remove unused parameter in function definition</title>
<updated>2022-10-18T10:52:25+00:00</updated>
<author>
<name>Fabien Parent</name>
<email>fabien.parent@linaro.org</email>
</author>
<published>2022-10-15T13:04:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a05887f005d374ff10aeaffe9f203e49fde22d17'/>
<id>a05887f005d374ff10aeaffe9f203e49fde22d17</id>
<content type='text'>
The speedbin_nvmem parameter is not used for
get_krait_bin_format_{a,b}. Let's remove the parameter to make the code
cleaner.

Signed-off-by: Fabien Parent &lt;fabien.parent@linaro.org&gt;
Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The speedbin_nvmem parameter is not used for
get_krait_bin_format_{a,b}. Let's remove the parameter to make the code
cleaner.

Signed-off-by: Fabien Parent &lt;fabien.parent@linaro.org&gt;
Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
