On Thu, 16 Feb 2017, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > On Fri, Feb 10, 2017 at 11:28:02AM +0100, Hans de Goede wrote: >> Listen for PMIC bus access notifications and get FORCEWAKE_ALL while >> the bus is accessed to avoid needing to do any forcewakes, which need >> PMIC bus access, while the PMIC bus is busy: >> >> This fixes errors like these showing up in dmesg, usually followed >> by a gfx or system freeze: >> >> [drm:fw_domains_get [i915]] *ERROR* render: timed out waiting for forcewake ack request. >> [drm:fw_domains_get [i915]] *MEDIA* render: timed out waiting for forcewake ack request. >> i2c_designware 808622C1:06: punit semaphore timed out, resetting >> i2c_designware 808622C1:06: PUNIT SEM: 2 >> i2c_designware 808622C1:06: couldn't acquire bus ownership >> >> Downside of this approach is that it causes wakeups whenever the PMIC >> bus is accessed. Unfortunately we cannot simply wait for the PMIC bus >> to go idle when we hit a race, as forcewakes may be done from interrupt >> handlers where we cannot sleep to wait for the i2c PMIC bus access to >> finish. >> >> Note that the notifications and thus the wakeups will only happen on >> baytrail / cherrytrail devices using PMICs with a shared i2c bus for >> P-Unit and host PMIC access (i2c busses with a _SEM method in their >> APCI node), e.g. an axp288 PMIC. >> >> I plan to write some patches for drivers accessing the PMIC bus to >> limit their bus accesses to a bare minimum (e.g. cache registers, do not >> update battery level more often then 4 times a minute), to limit the >> amount of wakeups. >> >> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241 >> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> >> Tested-by: tagorereddy <tagore.chandan@xxxxxxxxx> > > I gave the previous versions a quick whirl on a few machines here, but > them not being CR versions I guess this stuff doesn't kick in at all. > And I don't see any _SEM stuff in the DSDT/SSDT, so I guess that > confirms it. Which is fine since I've not seem any stability issues > on those machines. So at least nothing seemed to break :) > > Anyways the changes look all right to me, so for both i915 patches > Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Acked-by: Jani Nikula <jani.nikula@xxxxxxxxx> for merging the i915 patches through some other tree if that makes managing the pile easier. > >> --- >> Changes in v2: >> -Spelling: P-Unit, PMIC >> Changes in v3: >> -Improve comment explaining why we call intel_uncore_forcewake_get(ALL) on >> MBI_PMIC_BUS_ACCESS_BEGIN notification >> --- >> drivers/gpu/drm/i915/Kconfig | 1 + >> drivers/gpu/drm/i915/i915_drv.h | 1 + >> drivers/gpu/drm/i915/intel_uncore.c | 39 +++++++++++++++++++++++++++++++++++++ >> 3 files changed, 41 insertions(+) >> >> diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig >> index 1ae0bb9..a5cd5da 100644 >> --- a/drivers/gpu/drm/i915/Kconfig >> +++ b/drivers/gpu/drm/i915/Kconfig >> @@ -20,6 +20,7 @@ config DRM_I915 >> select ACPI_VIDEO if ACPI >> select ACPI_BUTTON if ACPI >> select SYNC_FILE >> + select IOSF_MBI >> help >> Choose this option if you have a system that has "Intel Graphics >> Media Accelerator" or "HD Graphics" integrated graphics, >> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h >> index 998239f..4e405d0 100644 >> --- a/drivers/gpu/drm/i915/i915_drv.h >> +++ b/drivers/gpu/drm/i915/i915_drv.h >> @@ -725,6 +725,7 @@ struct intel_uncore { >> const struct intel_forcewake_range *fw_domains_table; >> unsigned int fw_domains_table_entries; >> >> + struct notifier_block pmic_bus_access_nb; >> struct intel_uncore_funcs funcs; >> >> unsigned fifo_count; >> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c >> index b6d726b..1be3cdc 100644 >> --- a/drivers/gpu/drm/i915/intel_uncore.c >> +++ b/drivers/gpu/drm/i915/intel_uncore.c >> @@ -25,6 +25,7 @@ >> #include "intel_drv.h" >> #include "i915_vgpu.h" >> >> +#include <asm/iosf_mbi.h> >> #include <linux/pm_runtime.h> >> >> #define FORCEWAKE_ACK_TIMEOUT_MS 50 >> @@ -436,12 +437,16 @@ static void __intel_uncore_early_sanitize(struct drm_i915_private *dev_priv, >> >> void intel_uncore_suspend(struct drm_i915_private *dev_priv) >> { >> + iosf_mbi_unregister_pmic_bus_access_notifier( >> + &dev_priv->uncore.pmic_bus_access_nb); >> intel_uncore_forcewake_reset(dev_priv, false); >> } >> >> void intel_uncore_resume_early(struct drm_i915_private *dev_priv) >> { >> __intel_uncore_early_sanitize(dev_priv, true); >> + iosf_mbi_register_pmic_bus_access_notifier( >> + &dev_priv->uncore.pmic_bus_access_nb); >> i915_check_and_clear_faults(dev_priv); >> } >> >> @@ -1329,6 +1334,32 @@ static void intel_uncore_fw_domains_init(struct drm_i915_private *dev_priv) >> dev_priv->uncore.fw_domains_table_entries = ARRAY_SIZE((d)); \ >> } >> >> +static int i915_pmic_bus_access_notifier(struct notifier_block *nb, >> + unsigned long action, void *data) >> +{ >> + struct drm_i915_private *dev_priv = container_of(nb, >> + struct drm_i915_private, uncore.pmic_bus_access_nb); >> + >> + switch (action) { >> + case MBI_PMIC_BUS_ACCESS_BEGIN: >> + /* >> + * forcewake all now to make sure that we don't need to do a >> + * forcewake later which on systems where this notifier gets >> + * called requires the punit to access to the shared pmic i2c >> + * bus, which will be busy after this notification, leading to: >> + * "render: timed out waiting for forcewake ack request." >> + * errors. >> + */ >> + intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL); >> + break; >> + case MBI_PMIC_BUS_ACCESS_END: >> + intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL); >> + break; >> + } >> + >> + return NOTIFY_OK; >> +} >> + >> void intel_uncore_init(struct drm_i915_private *dev_priv) >> { >> i915_check_vgpu(dev_priv); >> @@ -1338,6 +1369,8 @@ void intel_uncore_init(struct drm_i915_private *dev_priv) >> __intel_uncore_early_sanitize(dev_priv, false); >> >> dev_priv->uncore.unclaimed_mmio_check = 1; >> + dev_priv->uncore.pmic_bus_access_nb.notifier_call = >> + i915_pmic_bus_access_notifier; >> >> switch (INTEL_INFO(dev_priv)->gen) { >> default: >> @@ -1392,6 +1425,9 @@ void intel_uncore_init(struct drm_i915_private *dev_priv) >> if (INTEL_GEN(dev_priv) >= 8) >> intel_shadow_table_check(); >> >> + iosf_mbi_register_pmic_bus_access_notifier( >> + &dev_priv->uncore.pmic_bus_access_nb); >> + >> i915_check_and_clear_faults(dev_priv); >> } >> #undef ASSIGN_WRITE_MMIO_VFUNCS >> @@ -1399,6 +1435,9 @@ void intel_uncore_init(struct drm_i915_private *dev_priv) >> >> void intel_uncore_fini(struct drm_i915_private *dev_priv) >> { >> + iosf_mbi_unregister_pmic_bus_access_notifier( >> + &dev_priv->uncore.pmic_bus_access_nb); >> + >> /* Paranoia: make sure we have disabled everything before we exit. */ >> intel_uncore_sanitize(dev_priv); >> intel_uncore_forcewake_reset(dev_priv, false); >> -- >> 2.9.3 -- Jani Nikula, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
