[Intel-gfx] [PATCH 08/13] drm/i915/tc: Refactor TC-cold block/unblock helpers
Imre Deak
imre.deak at intel.com
Mon Sep 27 23:51:27 UTC 2021
On Tue, Sep 28, 2021 at 02:33:27AM +0300, Souza, Jose wrote:
> On Tue, 2021-09-28 at 01:28 +0300, Imre Deak wrote:
> > On Tue, Sep 28, 2021 at 01:21:21AM +0300, Souza, Jose wrote:
> > > On Tue, 2021-09-28 at 01:13 +0300, Imre Deak wrote:
> > > > On Tue, Sep 28, 2021 at 12:56:24AM +0300, Souza, Jose wrote:
> > > > > On Tue, 2021-09-21 at 03:23 +0300, Imre Deak wrote:
> > > > > > A follow-up change will select the TC-cold blocking power domain based
> > > > > > on the TypeC mode, prepare for that here.
> > > > > >
> > > > > > Also bring intel_tc_cold_requires_aux_pw() earlier to its logical place
> > > > > > for readability.
> > > > > >
> > > > > > No functional change.
> > > > > >
> > > > > > Cc: José Roberto de Souza <jose.souza at intel.com>
> > > > > > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > > > > > ---
> > > > > > .../drm/i915/display/intel_display_types.h | 2 +
> > > > > > drivers/gpu/drm/i915/display/intel_tc.c | 63 +++++++++++--------
> > > > > > 2 files changed, 39 insertions(+), 26 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > > > index e9e806d90eec4..08a73ffded957 100644
> > > > > > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > > > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > > > @@ -1663,8 +1663,10 @@ struct intel_digital_port {
> > > > > > enum intel_display_power_domain ddi_io_power_domain;
> > > > > > intel_wakeref_t ddi_io_wakeref;
> > > > > > intel_wakeref_t aux_wakeref;
> > > > > > +
> > > > > > struct mutex tc_lock; /* protects the TypeC port mode */
> > > > > > intel_wakeref_t tc_lock_wakeref;
> > > > > > + enum intel_display_power_domain tc_lock_power_domain;
> > > > > > int tc_link_refcount;
> > > > > > bool tc_legacy_port:1;
> > > > > > char tc_port_name[8];
> > > > > > diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c
> > > > > > index 77b16a7c43466..24d2dc2e19a7d 100644
> > > > > > --- a/drivers/gpu/drm/i915/display/intel_tc.c
> > > > > > +++ b/drivers/gpu/drm/i915/display/intel_tc.c
> > > > > > @@ -48,8 +48,16 @@ bool intel_tc_port_in_legacy_mode(struct intel_digital_port *dig_port)
> > > > > > return intel_tc_port_in_mode(dig_port, TC_PORT_LEGACY);
> > > > > > }
> > > > > >
> > > > > > +bool intel_tc_cold_requires_aux_pw(struct intel_digital_port *dig_port)
> > > > > > +{
> > > > > > + struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> > > > > > +
> > > > > > + return (DISPLAY_VER(i915) == 11 && dig_port->tc_legacy_port) ||
> > > > > > + IS_ALDERLAKE_P(i915);
> > > > > > +}
> > > > > > +
> > > > > > static enum intel_display_power_domain
> > > > > > -tc_cold_get_power_domain(struct intel_digital_port *dig_port)
> > > > > > +tc_cold_get_power_domain(struct intel_digital_port *dig_port, enum tc_port_mode mode)
> > > > > > {
> > > > > > if (intel_tc_cold_requires_aux_pw(dig_port))
> > > > > > return intel_legacy_aux_to_power_domain(dig_port->aux_ch);
> > > > > > @@ -58,23 +66,30 @@ tc_cold_get_power_domain(struct intel_digital_port *dig_port)
> > > > > > }
> > > > > >
> > > > > > static intel_wakeref_t
> > > > > > -tc_cold_block(struct intel_digital_port *dig_port)
> > > > > > +tc_cold_block_in_mode(struct intel_digital_port *dig_port, enum tc_port_mode mode,
> > > > > > + enum intel_display_power_domain *domain)
> > > > > > {
> > > > > > struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> > > > > > - enum intel_display_power_domain domain;
> > > > > >
> > > > > > if (DISPLAY_VER(i915) == 11 && !dig_port->tc_legacy_port)
> > > > > > return 0;
> > > > > >
> > > > > > - domain = tc_cold_get_power_domain(dig_port);
> > > > > > - return intel_display_power_get(i915, domain);
> > > > > > + *domain = tc_cold_get_power_domain(dig_port, mode);
> > > > >
> > > > > I see problems with this approach.
> > > > >
> > > > > If there is a TC alt-mode is connected and current software state is
> > > > > TBT or disconnected it will not get the power domain to exit TC cold,
> > > > > what could case invalid reads of registers.
> > > >
> > > > If the mode needs to be changed, like in the above cases, the power
> > > > domain required to exit TC cold will be taken.
> > >
> > > How?
> > > I see at least this 2 problematic cases.
> > >
> > > intel_tc_port_sanitize()
> > > tc_cold_block(mode=TBT)
> >
> > It's in disconnected mode at this point.
>
> Okay.
>
> >
> > >
> > > dig_port->tc_mode = intel_tc_port_get_current_mode(dig_port);
> > > ...
> > >
> > > tc_cold_unblock(dig_port, domain, tc_cold_wref);
> > >
> > > Other case
> > >
> > > intel_tc_port_connected()
> > >
> > > tc_cold_block(mode=TBT)
> >
> > Reading PORT_TX_DFLEXDPSP while in TC-cold returns 0xffffffff, and it's
> > handled when reading it (which is also required by the spec).
>
> Will only follow adl-p flow for this
> example, https://pastebin.com/raw/TVXdK1Et (pastebin just to make sure
> indentation is not lost between email clients)
TCSS_DDI_STATUS is in IOM (so neither a FIA or a PHY register). From Bspec 55480:
"""
Type-C Flow Registers Used by Display Software
...
Location Register
IOM TCSS_DDI_STATUS
"""
and IOM registers are accessible in TC-cold:
"""
TCCOLD
The type-C subsystem can enter the TCCOLD power saving state where FIA and type-C
PHY registers become inaccessible and respond to reads with all 1s data,
while IOM remains accessible.
"""
> > > BIT(dig_port->tc_mode);
> > >
> > > tc_cold_unblock(dig_port, domain, tc_cold_wref);
> > >
> > >
> > > >
> > > > > From the next patch commit message: 'For the ADL-P TBT mode the spec
> > > > > doesn't require blocking TC-cold by using the legacy AUX power
> > > > > domain'.
> > > > >
> > > > > It is not required for TBT but when there is nothing connected,
> > > > > hardware is not in TBT mode so it can still get into TC cold.
> > > >
> > > > If there is nothing connected the required power domain will be taken to
> > > > exit TC cold.
> > > >
> > > > > > +
> > > > > > + return intel_display_power_get(i915, *domain);
> > > > > > +}
> > > > > > +
> > > > > > +static intel_wakeref_t
> > > > > > +tc_cold_block(struct intel_digital_port *dig_port, enum intel_display_power_domain *domain)
> > > > > > +{
> > > > > > + return tc_cold_block_in_mode(dig_port, dig_port->tc_mode, domain);
> > > > > > }
> > > > > >
> > > > > > static void
> > > > > > -tc_cold_unblock(struct intel_digital_port *dig_port, intel_wakeref_t wakeref)
> > > > > > +tc_cold_unblock(struct intel_digital_port *dig_port, enum intel_display_power_domain domain,
> > > > > > + intel_wakeref_t wakeref)
> > > > > > {
> > > > > > struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> > > > > > - enum intel_display_power_domain domain;
> > > > > >
> > > > > > /*
> > > > > > * wakeref == -1, means some error happened saving save_depot_stack but
> > > > > > @@ -84,8 +99,7 @@ tc_cold_unblock(struct intel_digital_port *dig_port, intel_wakeref_t wakeref)
> > > > > > if (wakeref == 0)
> > > > > > return;
> > > > > >
> > > > > > - domain = tc_cold_get_power_domain(dig_port);
> > > > > > - intel_display_power_put_async(i915, domain, wakeref);
> > > > > > + intel_display_power_put(i915, domain, wakeref);
> > > > > > }
> > > > > >
> > > > > > static void
> > > > > > @@ -98,7 +112,8 @@ assert_tc_cold_blocked(struct intel_digital_port *dig_port)
> > > > > > return;
> > > > > >
> > > > > > enabled = intel_display_power_is_enabled(i915,
> > > > > > - tc_cold_get_power_domain(dig_port));
> > > > > > + tc_cold_get_power_domain(dig_port,
> > > > > > + dig_port->tc_mode));
> > > > > > drm_WARN_ON(&i915->drm, !enabled);
> > > > > > }
> > > > > >
> > > > > > @@ -634,7 +649,8 @@ void intel_tc_port_sanitize(struct intel_digital_port *dig_port)
> > > > > >
> > > > > > drm_WARN_ON(&i915->drm, dig_port->tc_mode != TC_PORT_DISCONNECTED);
> > > > > > if (active_links) {
> > > > > > - intel_wakeref_t tc_cold_wref = tc_cold_block(dig_port);
> > > > > > + enum intel_display_power_domain domain;
> > > > > > + intel_wakeref_t tc_cold_wref = tc_cold_block(dig_port, &domain);
> > > > > >
> > > > > > dig_port->tc_mode = intel_tc_port_get_current_mode(dig_port);
> > > > > >
> > > > > > @@ -644,7 +660,7 @@ void intel_tc_port_sanitize(struct intel_digital_port *dig_port)
> > > > > > dig_port->tc_port_name, active_links);
> > > > > > intel_tc_port_link_init_refcount(dig_port, active_links);
> > > > > >
> > > > > > - tc_cold_unblock(dig_port, tc_cold_wref);
> > > > > > + tc_cold_unblock(dig_port, domain, tc_cold_wref);
> > > > > > }
> > > > > >
> > > > > > drm_dbg_kms(&i915->drm, "Port %s: sanitize mode (%s)\n",
> > > > > > @@ -673,15 +689,16 @@ bool intel_tc_port_connected(struct intel_encoder *encoder)
> > > > > > {
> > > > > > struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
> > > > > > bool is_connected;
> > > > > > + enum intel_display_power_domain domain;
> > > > > > intel_wakeref_t tc_cold_wref;
> > > > > >
> > > > > > intel_tc_port_lock(dig_port);
> > > > > > - tc_cold_wref = tc_cold_block(dig_port);
> > > > > > + tc_cold_wref = tc_cold_block(dig_port, &domain);
> > > > > >
> > > > > > is_connected = tc_port_live_status_mask(dig_port) &
> > > > > > BIT(dig_port->tc_mode);
> > > > > >
> > > > > > - tc_cold_unblock(dig_port, tc_cold_wref);
> > > > > > + tc_cold_unblock(dig_port, domain, tc_cold_wref);
> > > > > > intel_tc_port_unlock(dig_port);
> > > > > >
> > > > > > return is_connected;
> > > > > > @@ -698,15 +715,16 @@ static void __intel_tc_port_lock(struct intel_digital_port *dig_port,
> > > > > > mutex_lock(&dig_port->tc_lock);
> > > > > >
> > > > > > if (!dig_port->tc_link_refcount) {
> > > > > > + enum intel_display_power_domain domain;
> > > > > > intel_wakeref_t tc_cold_wref;
> > > > > >
> > > > > > - tc_cold_wref = tc_cold_block(dig_port);
> > > > > > + tc_cold_wref = tc_cold_block(dig_port, &domain);
> > > > > >
> > > > > > if (force_disconnect || intel_tc_port_needs_reset(dig_port))
> > > > > > intel_tc_port_reset_mode(dig_port, required_lanes,
> > > > > > force_disconnect);
> > > > > >
> > > > > > - tc_cold_unblock(dig_port, tc_cold_wref);
> > > > > > + tc_cold_unblock(dig_port, domain, tc_cold_wref);
> > > > > > }
> > > > > >
> > > > > > drm_WARN_ON(&i915->drm, dig_port->tc_mode == TC_PORT_DISCONNECTED);
> > > > > > @@ -775,6 +793,7 @@ void intel_tc_port_put_link(struct intel_digital_port *dig_port)
> > > > > > static bool
> > > > > > tc_has_modular_fia(struct drm_i915_private *i915, struct intel_digital_port *dig_port)
> > > > > > {
> > > > > > + enum intel_display_power_domain domain;
> > > > > > intel_wakeref_t wakeref;
> > > > > > u32 val;
> > > > > >
> > > > > > @@ -782,9 +801,9 @@ tc_has_modular_fia(struct drm_i915_private *i915, struct intel_digital_port *dig
> > > > > > return false;
> > > > > >
> > > > > > mutex_lock(&dig_port->tc_lock);
> > > > > > - wakeref = tc_cold_block(dig_port);
> > > > > > + wakeref = tc_cold_block(dig_port, &domain);
> > > > > > val = intel_uncore_read(&i915->uncore, PORT_TX_DFLEXDPSP(FIA1));
> > > > > > - tc_cold_unblock(dig_port, wakeref);
> > > > > > + tc_cold_unblock(dig_port, domain, wakeref);
> > > > > > mutex_unlock(&dig_port->tc_lock);
> > > > > >
> > > > > > drm_WARN_ON(&i915->drm, val == 0xffffffff);
> > > > > > @@ -829,11 +848,3 @@ void intel_tc_port_init(struct intel_digital_port *dig_port, bool is_legacy)
> > > > > > dig_port->tc_link_refcount = 0;
> > > > > > tc_port_load_fia_params(i915, dig_port);
> > > > > > }
> > > > > > -
> > > > > > -bool intel_tc_cold_requires_aux_pw(struct intel_digital_port *dig_port)
> > > > > > -{
> > > > > > - struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> > > > > > -
> > > > > > - return (DISPLAY_VER(i915) == 11 && dig_port->tc_legacy_port) ||
> > > > > > - IS_ALDERLAKE_P(i915);
> > > > > > -}
> > > > >
> > >
>
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