[Intel-gfx] [PATCH 07/11] drm/i915/dp: Exit PSR before do a aux channel transaction
Souza, Jose
jose.souza at intel.com
Mon Apr 2 23:21:41 UTC 2018
On Mon, 2018-04-02 at 22:16 +0000, Souza, Jose wrote:
> On Mon, 2018-04-02 at 11:42 -0700, Pandiyan, Dhinakaran wrote:
> >
> >
> > On Mon, 2018-04-02 at 11:23 -0700, Rodrigo Vivi wrote:
> > > On Fri, Mar 30, 2018 at 03:23:32PM -0700, José Roberto de Souza
> > > wrote:
> > > > When PSR/PSR2 is enabled hardware can do aux ch transactions by
> > > > it
> > > > self.
> > > > Spec requires that PSR is inactive before do any aux ch
> > > > transaction
> > > > in HSW and BDW, for skl+ there is a aux ch mutex but the use is
> > > > not
> > > > recommended.
> > > > So exiting PSR/PSR2 and waiting the transition to inactive to
> > > > prevent
> > > > any concurrent access between hardware and software in aux ch
> > > > registers.
> > > >
> > > > VLV and CHV hardware don't do any aux as software is
> > > > responsible
> > > > to
> > > > do all the buffer tracking and it sends the wake up aux ch
> > > > message
> > > > to sink.
> > > >
> > >
> > > ahh cool... I get back what I said on some previous patch.
> > > I like where it is going, but...
> > >
> > > > BSpec: 7530, 799 and 7532
> > > >
> > > > Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> > > > Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > > > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > > > ---
> > > > drivers/gpu/drm/i915/intel_dp.c | 38
> > > > ++++++++++++++++++++++++++++++++++++++
> > > > drivers/gpu/drm/i915/intel_drv.h | 2 ++
> > > > drivers/gpu/drm/i915/intel_psr.c | 8 ++++++++
> > > > 3 files changed, 48 insertions(+)
> > > >
> > > > diff --git a/drivers/gpu/drm/i915/intel_dp.c
> > > > b/drivers/gpu/drm/i915/intel_dp.c
> > > > index 62f82c4298ac..fedee4e7ed24 100644
> > > > --- a/drivers/gpu/drm/i915/intel_dp.c
> > > > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > > > @@ -1062,6 +1062,41 @@ static uint32_t
> > > > skl_get_aux_send_ctl(struct intel_dp *intel_dp,
> > > > DP_AUX_CH_CTL_SYNC_PULSE_SKL(32);
> > > > }
> > > >
> > > > +/**
> > > > + * intel_dp_aux_ch_get - Get total control of aux ch registers
> > > > + *
> > > > + * By exiting or disabling any hardware feature that can also
> > > > use the aux ch
> > > > + * registers at the same time as driver, this function will
> > > > give
> > > > total control
> > > > + * of aux ch registers to driver.
> > > > + */
> > > > +static void intel_dp_aux_ch_get(struct intel_dp *intel_dp)
> > > > +{
> > > > + if (!intel_dp->exit_psr_on_aux_ch_xfer)
> > > > + return;
> > > > +
> > > > + intel_psr_activate_block_get(intel_dp);
> > > > + intel_psr_exit(intel_dp, true);
> > >
> > > decision on exit and activate should be inside the block_get and
> > > block_put,
> > > based on current state of the counters.
> > >
> >
> > I haven't read the patches yet, but you could use the kref
> > infrastructure for
> > reference counting.
>
> Cool I will use it, thanks.
To use kref I would need to do something like this in intel_psr_init():
kref_init(&dev_priv->psr.activate_block_kref);
/* kref_init() initialize the reference as 1, so calling kref_put() to
* keep it as 0 but this will cause the release callback to be executed
* but it will not be fully executed as PSR is not enabled yet.
*/
kref_put(&dev_priv->psr.activate_block_kref,
intel_psr_activate_block_release);
That is okay? keep it?
>
> >
> > > > +}
> > > > +
> > > > +/**
> > > > + * intel_dp_aux_ch_put - Release aux ch registers control
> > > > + *
> > > > + * It is the intel_dp_aux_ch_get() counterpart.
> > > > + */
> > > > +static void intel_dp_aux_ch_put(struct intel_dp *intel_dp)
> > > > +{
> > > > + if (!intel_dp->exit_psr_on_aux_ch_xfer)
> > > > + return;
> > > > +
> > > > + intel_psr_activate_block_put(intel_dp);
> > > > + /* Usually more than just one aux ch transaction is
> > > > executed when
> > > > + * handling some event, activating PSR right way would
> > > > cause several
> > > > + * msecs of delay waiting PSR to exit for each aux ch
> > > > transaction, so
> > > > + * here asking it to be scheduled.
> > > > + */
> > > > + intel_psr_activate(intel_dp, true);
> > > > +}
> > > > +
> > > > static int
> > > > intel_dp_aux_xfer(struct intel_dp *intel_dp,
> > > > const uint8_t *send, int send_bytes,
> > > > @@ -1101,6 +1136,8 @@ intel_dp_aux_xfer(struct intel_dp
> > > > *intel_dp,
> > > >
> > > > intel_dp_check_edp(intel_dp);
> > > >
> > > > + intel_dp_aux_ch_get(intel_dp);
> > > > +
> > > > /* Try to wait for any previous AUX channel activity
> > > > */
> > > > for (try = 0; try < 3; try++) {
> > > > status = I915_READ_NOTRACE(ch_ctl);
> > > > @@ -1223,6 +1260,7 @@ intel_dp_aux_xfer(struct intel_dp
> > > > *intel_dp,
> > > >
> > > > ret = recv_bytes;
> > > > out:
> > > > + intel_dp_aux_ch_put(intel_dp);
> > > > pm_qos_update_request(&dev_priv->pm_qos,
> > > > PM_QOS_DEFAULT_VALUE);
> > > >
> > > > if (vdd)
> > > > diff --git a/drivers/gpu/drm/i915/intel_drv.h
> > > > b/drivers/gpu/drm/i915/intel_drv.h
> > > > index 020b96324135..177478f0b032 100644
> > > > --- a/drivers/gpu/drm/i915/intel_drv.h
> > > > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > > > @@ -1139,6 +1139,8 @@ struct intel_dp {
> > > >
> > > > /* Displayport compliance testing */
> > > > struct intel_dp_compliance compliance;
> > > > +
> > > > + bool exit_psr_on_aux_ch_xfer;
> > > > };
> > > >
> > > > struct intel_lspcon {
> > > > diff --git a/drivers/gpu/drm/i915/intel_psr.c
> > > > b/drivers/gpu/drm/i915/intel_psr.c
> > > > index 8702dbafb42d..f88f12246a23 100644
> > > > --- a/drivers/gpu/drm/i915/intel_psr.c
> > > > +++ b/drivers/gpu/drm/i915/intel_psr.c
> > > > @@ -665,6 +665,13 @@ void intel_psr_enable(struct intel_dp
> > > > *intel_dp,
> > > > msecs_to_jiffies(intel_d
> > > > p-
> > > > > panel_power_cycle_delay * 5));
> > > >
> > > > }
> > > >
> > > > + /* From all platforms that supports PSR/PSR2 this 2 is
> > > > the ones that
> > > > + * don't have restrictions about use of the aux ch
> > > > while
> > > > PSR/PSR2 is
> > > > + * enabled.
> > > > + */
> > > > + if (!(IS_VALLEYVIEW(dev_priv) ||
> > > > IS_CHERRYVIEW(dev_priv)))
> > > > + intel_dp->exit_psr_on_aux_ch_xfer = true;
> > > > +
> > > > unlock:
> > > > mutex_unlock(&dev_priv->psr.lock);
> > > > }
> > > > @@ -732,6 +739,7 @@ void intel_psr_disable(struct intel_dp
> > > > *intel_dp,
> > > >
> > > > dev_priv->psr.disable_source(intel_dp);
> > > >
> > > > + intel_dp->exit_psr_on_aux_ch_xfer = false;
> > > > /* Disable PSR on Sink */
> > > > drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_EN_CFG, 0);
> > > >
> > > > --
> > > > 2.16.3
> > > >
>
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