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Message-ID: <529CA5D5.9010008@gmail.com>
Date: Mon, 02 Dec 2013 07:23:01 -0800
From: Dirk Brandewie <dirk.brandewie@...il.com>
To: Viresh Kumar <viresh.kumar@...aro.org>, rjw@...ysocki.net
CC: linaro-kernel@...ts.linaro.org, patches@...aro.org,
cpufreq@...r.kernel.org, linux-pm@...r.kernel.org,
linux-kernel@...r.kernel.org, nm@...com, ceh@...com
Subject: Re: [PATCH V4 1/2] cpufreq: Mark x86 drivers with CPUFREQ_SKIP_INITIAL_FREQ_CHECK
flag
Sorry for late response to these threads. Holiday weekend in the US.
On 11/29/2013 06:14 AM, Viresh Kumar wrote:
> On some systems we can't really say what frequency we're running at the moment
> and so for these we shouldn't check if we are running at a frequency present in
> frequency table. For now mark all x86 drivers with this flag:
> CPUFREQ_SKIP_INITIAL_FREQ_CHECK.
>
> This patch also defines this macro. It will be used in cpufreq.c in the next
> patch.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
> V3->V4:
> - Reversed the order of patches
> - Moved definition of CPUFREQ_SKIP_INITIAL_FREQ_CHECK to patch 1/2 instead of
> 2/2.
>
> drivers/cpufreq/acpi-cpufreq.c | 1 +
> drivers/cpufreq/cpufreq-nforce2.c | 1 +
> drivers/cpufreq/e_powersaver.c | 1 +
> drivers/cpufreq/elanfreq.c | 1 +
> drivers/cpufreq/gx-suspmod.c | 1 +
> drivers/cpufreq/ia64-acpi-cpufreq.c | 1 +
> drivers/cpufreq/intel_pstate.c | 2 +-
NAK for intel_pstate. The code that will use this flag also uses has_target()
which is false for intel_pstate.
I think the logic for this patch is inverted. Why are we adding a flag to
drivers where the bug cannot exist? I would be happier if the flag was
CPUFREQ_NEED_INITIAL_FREQ_WORKAROUND to mark the platforms where the bug may
exist let those platforms cary the flag for the next 10+ years.
I still believe that this bug should be dealt with in platform specific code
since this is working around a bootloader bug. Are there platforms in the wild
that even need this code or is this to support early platform bringup?
> drivers/cpufreq/longhaul.c | 1 +
> drivers/cpufreq/longrun.c | 2 +-
> drivers/cpufreq/p4-clockmod.c | 1 +
> drivers/cpufreq/pcc-cpufreq.c | 2 +-
> drivers/cpufreq/powernow-k6.c | 1 +
> drivers/cpufreq/powernow-k7.c | 1 +
> drivers/cpufreq/powernow-k8.c | 3 ++-
> drivers/cpufreq/sc520_freq.c | 1 +
> drivers/cpufreq/speedstep-centrino.c | 1 +
> drivers/cpufreq/speedstep-ich.c | 1 +
> drivers/cpufreq/speedstep-smi.c | 1 +
> include/linux/cpufreq.h | 9 +++++++++
> 19 files changed, 28 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
> index caf41eb..b8e4f79 100644
> --- a/drivers/cpufreq/acpi-cpufreq.c
> +++ b/drivers/cpufreq/acpi-cpufreq.c
> @@ -903,6 +903,7 @@ static struct freq_attr *acpi_cpufreq_attr[] = {
> };
>
> static struct cpufreq_driver acpi_cpufreq_driver = {
> + .flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .verify = cpufreq_generic_frequency_table_verify,
> .target_index = acpi_cpufreq_target,
> .bios_limit = acpi_processor_get_bios_limit,
> diff --git a/drivers/cpufreq/cpufreq-nforce2.c b/drivers/cpufreq/cpufreq-nforce2.c
> index a05b876..b3222f6 100644
> --- a/drivers/cpufreq/cpufreq-nforce2.c
> +++ b/drivers/cpufreq/cpufreq-nforce2.c
> @@ -370,6 +370,7 @@ static int nforce2_cpu_exit(struct cpufreq_policy *policy)
> }
>
> static struct cpufreq_driver nforce2_driver = {
> + .flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .name = "nforce2",
> .verify = nforce2_verify,
> .target = nforce2_target,
> diff --git a/drivers/cpufreq/e_powersaver.c b/drivers/cpufreq/e_powersaver.c
> index 9012b8b..0826bda 100644
> --- a/drivers/cpufreq/e_powersaver.c
> +++ b/drivers/cpufreq/e_powersaver.c
> @@ -389,6 +389,7 @@ static int eps_cpu_exit(struct cpufreq_policy *policy)
> }
>
> static struct cpufreq_driver eps_driver = {
> + .flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .verify = cpufreq_generic_frequency_table_verify,
> .target_index = eps_target,
> .init = eps_cpu_init,
> diff --git a/drivers/cpufreq/elanfreq.c b/drivers/cpufreq/elanfreq.c
> index de08acf..426d14d 100644
> --- a/drivers/cpufreq/elanfreq.c
> +++ b/drivers/cpufreq/elanfreq.c
> @@ -194,6 +194,7 @@ __setup("elanfreq=", elanfreq_setup);
>
>
> static struct cpufreq_driver elanfreq_driver = {
> + .flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .get = elanfreq_get_cpu_frequency,
> .verify = cpufreq_generic_frequency_table_verify,
> .target_index = elanfreq_target,
> diff --git a/drivers/cpufreq/gx-suspmod.c b/drivers/cpufreq/gx-suspmod.c
> index d83e826..7bfad48 100644
> --- a/drivers/cpufreq/gx-suspmod.c
> +++ b/drivers/cpufreq/gx-suspmod.c
> @@ -438,6 +438,7 @@ static int cpufreq_gx_cpu_init(struct cpufreq_policy *policy)
> * MediaGX/Geode GX initialize cpufreq driver
> */
> static struct cpufreq_driver gx_suspmod_driver = {
> + .flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .get = gx_get_cpuspeed,
> .verify = cpufreq_gx_verify,
> .target = cpufreq_gx_target,
> diff --git a/drivers/cpufreq/ia64-acpi-cpufreq.c b/drivers/cpufreq/ia64-acpi-cpufreq.c
> index 53c6ac6..907bf9a 100644
> --- a/drivers/cpufreq/ia64-acpi-cpufreq.c
> +++ b/drivers/cpufreq/ia64-acpi-cpufreq.c
> @@ -344,6 +344,7 @@ acpi_cpufreq_cpu_exit (
>
>
> static struct cpufreq_driver acpi_cpufreq_driver = {
> + .flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .verify = cpufreq_generic_frequency_table_verify,
> .target_index = acpi_cpufreq_target,
> .get = acpi_cpufreq_get,
> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> index 5f1cbae..6c8f5d3 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -725,7 +725,7 @@ static int intel_pstate_cpu_init(struct cpufreq_policy *policy)
> }
>
> static struct cpufreq_driver intel_pstate_driver = {
> - .flags = CPUFREQ_CONST_LOOPS,
> + .flags = CPUFREQ_CONST_LOOPS | CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .verify = intel_pstate_verify_policy,
> .setpolicy = intel_pstate_set_policy,
> .get = intel_pstate_get,
> diff --git a/drivers/cpufreq/longhaul.c b/drivers/cpufreq/longhaul.c
> index 45bafdd..16c0a37 100644
> --- a/drivers/cpufreq/longhaul.c
> +++ b/drivers/cpufreq/longhaul.c
> @@ -909,6 +909,7 @@ static int longhaul_cpu_init(struct cpufreq_policy *policy)
> }
>
> static struct cpufreq_driver longhaul_driver = {
> + .flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .verify = cpufreq_generic_frequency_table_verify,
> .target_index = longhaul_target,
> .get = longhaul_get,
> diff --git a/drivers/cpufreq/longrun.c b/drivers/cpufreq/longrun.c
> index 074971b..b67d341 100644
> --- a/drivers/cpufreq/longrun.c
> +++ b/drivers/cpufreq/longrun.c
> @@ -278,7 +278,7 @@ static int longrun_cpu_init(struct cpufreq_policy *policy)
>
>
> static struct cpufreq_driver longrun_driver = {
> - .flags = CPUFREQ_CONST_LOOPS,
> + .flags = CPUFREQ_CONST_LOOPS | CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .verify = longrun_verify_policy,
> .setpolicy = longrun_set_policy,
> .get = longrun_get,
> diff --git a/drivers/cpufreq/p4-clockmod.c b/drivers/cpufreq/p4-clockmod.c
> index 3d1cba9..92b7e2b 100644
> --- a/drivers/cpufreq/p4-clockmod.c
> +++ b/drivers/cpufreq/p4-clockmod.c
> @@ -234,6 +234,7 @@ static unsigned int cpufreq_p4_get(unsigned int cpu)
> }
>
> static struct cpufreq_driver p4clockmod_driver = {
> + .flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .verify = cpufreq_generic_frequency_table_verify,
> .target_index = cpufreq_p4_target,
> .init = cpufreq_p4_cpu_init,
> diff --git a/drivers/cpufreq/pcc-cpufreq.c b/drivers/cpufreq/pcc-cpufreq.c
> index e2b4f40..eafe4ca 100644
> --- a/drivers/cpufreq/pcc-cpufreq.c
> +++ b/drivers/cpufreq/pcc-cpufreq.c
> @@ -571,7 +571,7 @@ static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
> }
>
> static struct cpufreq_driver pcc_cpufreq_driver = {
> - .flags = CPUFREQ_CONST_LOOPS,
> + .flags = CPUFREQ_CONST_LOOPS | CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .get = pcc_get_freq,
> .verify = pcc_cpufreq_verify,
> .target = pcc_cpufreq_target,
> diff --git a/drivers/cpufreq/powernow-k6.c b/drivers/cpufreq/powernow-k6.c
> index 643e795..fe60021 100644
> --- a/drivers/cpufreq/powernow-k6.c
> +++ b/drivers/cpufreq/powernow-k6.c
> @@ -150,6 +150,7 @@ static unsigned int powernow_k6_get(unsigned int cpu)
> }
>
> static struct cpufreq_driver powernow_k6_driver = {
> + .flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .verify = cpufreq_generic_frequency_table_verify,
> .target_index = powernow_k6_target,
> .init = powernow_k6_cpu_init,
> diff --git a/drivers/cpufreq/powernow-k7.c b/drivers/cpufreq/powernow-k7.c
> index 946708a..4e67abc 100644
> --- a/drivers/cpufreq/powernow-k7.c
> +++ b/drivers/cpufreq/powernow-k7.c
> @@ -679,6 +679,7 @@ static int powernow_cpu_exit(struct cpufreq_policy *policy)
> }
>
> static struct cpufreq_driver powernow_driver = {
> + .flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .verify = cpufreq_generic_frequency_table_verify,
> .target_index = powernow_target,
> .get = powernow_get,
> diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
> index 0023c7d..ffe89ba 100644
> --- a/drivers/cpufreq/powernow-k8.c
> +++ b/drivers/cpufreq/powernow-k8.c
> @@ -1204,7 +1204,8 @@ out:
> }
>
> static struct cpufreq_driver cpufreq_amd64_driver = {
> - .flags = CPUFREQ_ASYNC_NOTIFICATION,
> + .flags = CPUFREQ_ASYNC_NOTIFICATION |
> + CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .verify = cpufreq_generic_frequency_table_verify,
> .target_index = powernowk8_target,
> .bios_limit = acpi_processor_get_bios_limit,
> diff --git a/drivers/cpufreq/sc520_freq.c b/drivers/cpufreq/sc520_freq.c
> index 6adb354..d6a1cf6 100644
> --- a/drivers/cpufreq/sc520_freq.c
> +++ b/drivers/cpufreq/sc520_freq.c
> @@ -89,6 +89,7 @@ static int sc520_freq_cpu_init(struct cpufreq_policy *policy)
>
>
> static struct cpufreq_driver sc520_freq_driver = {
> + .flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .get = sc520_freq_get_cpu_frequency,
> .verify = cpufreq_generic_frequency_table_verify,
> .target_index = sc520_freq_target,
> diff --git a/drivers/cpufreq/speedstep-centrino.c b/drivers/cpufreq/speedstep-centrino.c
> index 4e1daca..887fd43 100644
> --- a/drivers/cpufreq/speedstep-centrino.c
> +++ b/drivers/cpufreq/speedstep-centrino.c
> @@ -505,6 +505,7 @@ out:
> }
>
> static struct cpufreq_driver centrino_driver = {
> + .flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .name = "centrino", /* should be speedstep-centrino,
> but there's a 16 char limit */
> .init = centrino_cpu_init,
> diff --git a/drivers/cpufreq/speedstep-ich.c b/drivers/cpufreq/speedstep-ich.c
> index 7639b2b..67596e7 100644
> --- a/drivers/cpufreq/speedstep-ich.c
> +++ b/drivers/cpufreq/speedstep-ich.c
> @@ -307,6 +307,7 @@ static int speedstep_cpu_init(struct cpufreq_policy *policy)
>
>
> static struct cpufreq_driver speedstep_driver = {
> + .flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .name = "speedstep-ich",
> .verify = cpufreq_generic_frequency_table_verify,
> .target_index = speedstep_target,
> diff --git a/drivers/cpufreq/speedstep-smi.c b/drivers/cpufreq/speedstep-smi.c
> index 0f5326d..4f23289 100644
> --- a/drivers/cpufreq/speedstep-smi.c
> +++ b/drivers/cpufreq/speedstep-smi.c
> @@ -308,6 +308,7 @@ static int speedstep_resume(struct cpufreq_policy *policy)
> }
>
> static struct cpufreq_driver speedstep_driver = {
> + .flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
> .name = "speedstep-smi",
> .verify = cpufreq_generic_frequency_table_verify,
> .target_index = speedstep_target,
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index ee5fe9d..13b8802 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -252,6 +252,15 @@ struct cpufreq_driver {
> */
> #define CPUFREQ_ASYNC_NOTIFICATION (1 << 4)
>
> +/*
> + * Set by drivers which don't want cpufreq core to check if CPU is running at a
> + * frequency present in freq-table exposed by the driver. For other drivers if
> + * CPU is found running at an out of table freq, we will try to set it to a freq
> + * from the table. And if that fails, we will stop further boot process by
> + * issuing a BUG_ON().
> + */
> +#define CPUFREQ_SKIP_INITIAL_FREQ_CHECK (1 << 5)
> +
> int cpufreq_register_driver(struct cpufreq_driver *driver_data);
> int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
>
>
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