diff options
| author | Suraj Kandpal <suraj.kandpal@intel.com> | 2023-07-20 16:16:24 +0530 |
|---|---|---|
| committer | Uma Shankar <uma.shankar@intel.com> | 2023-07-26 10:28:13 +0530 |
| commit | 4948738e296c75de57e0c4a8e8ead1ff2c03fe00 (patch) | |
| tree | e6e5b6194fbb13f8e9eb60eeb332372a1560799e /drivers/gpu/drm/i915/display/intel_hotplug_irq.c | |
| parent | b364f3cd879888191290cabd8981b0e6bb3a6fdb (diff) | |
drm/i915/hotplug: Reduce SHPD_FILTER to 250us
On TGP, the RTC (always running) was reduced from 3MHz to 32KHz.
As a result of this change, when HPD active going low pulse or HPD IRQ
is presented and the refclk (19.2MHz) is not toggling already toggling,
there is a 60 to 90us synchronization delay which effectively reduces
the duration of the IRQ pulse to less than the programmed 500us filter
value and the hot plug interrupt is NOT registered.
Solution was to Reduce SHPD_FILTER to 250us for ADL and above.
This solution was derived when the below patch was floated.
[1]https://patchwork.freedesktop.org/patch/532187
and after some internal discussion Ville's suggestion made sense.
Bspec: 68970
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Suggested-by: Ville Syrjala <ville.syrjala@linux.intel.com>
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230720104624.3063544-1-suraj.kandpal@intel.com
Diffstat (limited to 'drivers/gpu/drm/i915/display/intel_hotplug_irq.c')
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_hotplug_irq.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_hotplug_irq.c b/drivers/gpu/drm/i915/display/intel_hotplug_irq.c index f95fa793fabb..95a7ea94f417 100644 --- a/drivers/gpu/drm/i915/display/intel_hotplug_irq.c +++ b/drivers/gpu/drm/i915/display/intel_hotplug_irq.c @@ -842,6 +842,8 @@ static void icp_hpd_irq_setup(struct drm_i915_private *dev_priv) if (INTEL_PCH_TYPE(dev_priv) <= PCH_TGP) intel_uncore_write(&dev_priv->uncore, SHPD_FILTER_CNT, SHPD_FILTER_CNT_500_ADJ); + else + intel_uncore_write(&dev_priv->uncore, SHPD_FILTER_CNT, SHPD_FILTER_CNT_250); ibx_display_interrupt_update(dev_priv, hotplug_irqs, enabled_irqs); @@ -1049,7 +1051,7 @@ static void mtp_hpd_irq_setup(struct drm_i915_private *i915) enabled_irqs = intel_hpd_enabled_irqs(i915, i915->display.hotplug.pch_hpd); hotplug_irqs = intel_hpd_hotplug_irqs(i915, i915->display.hotplug.pch_hpd); - intel_de_write(i915, SHPD_FILTER_CNT, SHPD_FILTER_CNT_500_ADJ); + intel_de_write(i915, SHPD_FILTER_CNT, SHPD_FILTER_CNT_250); mtp_hpd_invert(i915); ibx_display_interrupt_update(i915, hotplug_irqs, enabled_irqs); |