On Mon, 27 Mar 2023, Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> wrote: > uncore->lock only protects the forcewake domain itself, > not the register accesses. > > uncore's _fw alternatives are for cases where the domains > are not needed because we are sure that they are already > awake. > > So the move towards the uncore's _fw alternatives seems > right, however using the uncore-lock to protect the dsparb > registers seems an abuse of the uncore-lock. > > Let's restore the previous individual lock and try to get > rid of the direct uncore accesses from the display code. > > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > Cc: Jani Nikula <jani.nikula@xxxxxxxxx> > Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> > Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > Link: https://patchwork.freedesktop.org/patch/msgid/20230308165859.235520-1-rodrigo.vivi@xxxxxxxxx > --- > drivers/gpu/drm/i915/display/i9xx_wm.c | 13 ++----------- > drivers/gpu/drm/i915/display/intel_display_core.h | 3 +++ > drivers/gpu/drm/i915/i915_driver.c | 1 + > 3 files changed, 6 insertions(+), 11 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/i9xx_wm.c b/drivers/gpu/drm/i915/display/i9xx_wm.c > index caef72d38798..8fe0b5c63d3a 100644 > --- a/drivers/gpu/drm/i915/display/i9xx_wm.c > +++ b/drivers/gpu/drm/i915/display/i9xx_wm.c > @@ -1771,16 +1771,7 @@ static void vlv_atomic_update_fifo(struct intel_atomic_state *state, > > trace_vlv_fifo_size(crtc, sprite0_start, sprite1_start, fifo_size); > > - /* > - * uncore.lock serves a double purpose here. It allows us to > - * use the less expensive I915_{READ,WRITE}_FW() functions, and > - * it protects the DSPARB registers from getting clobbered by > - * parallel updates from multiple pipes. > - * > - * intel_pipe_update_start() has already disabled interrupts > - * for us, so a plain spin_lock() is sufficient here. > - */ > - spin_lock(&uncore->lock); > + spin_lock(&dev_priv->display.wm.dsparb_lock); > > switch (crtc->pipe) { > case PIPE_A: > @@ -1840,7 +1831,7 @@ static void vlv_atomic_update_fifo(struct intel_atomic_state *state, > > intel_uncore_posting_read_fw(uncore, DSPARB); > > - spin_unlock(&uncore->lock); > + spin_unlock(&dev_priv->display.wm.dsparb_lock); > } > > #undef VLV_FIFO > diff --git a/drivers/gpu/drm/i915/display/intel_display_core.h b/drivers/gpu/drm/i915/display/intel_display_core.h > index 0b5509f268a7..e4da8902c878 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_core.h > +++ b/drivers/gpu/drm/i915/display/intel_display_core.h > @@ -264,6 +264,9 @@ struct intel_wm { > */ > struct mutex wm_mutex; > > + /* protects DSPARB registers on pre-g4x/vlv/chv */ > + spinlock_t dsparb_lock; > + > bool ipc_enabled; > }; > > diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c > index 12b5296ee744..e90a0c0403a6 100644 > --- a/drivers/gpu/drm/i915/i915_driver.c > +++ b/drivers/gpu/drm/i915/i915_driver.c > @@ -223,6 +223,7 @@ static int i915_driver_early_probe(struct drm_i915_private *dev_priv) > mutex_init(&dev_priv->display.pps.mutex); > mutex_init(&dev_priv->display.hdcp.comp_mutex); > spin_lock_init(&dev_priv->display.dkl.phy_lock); > + spin_lock_init(&dev_priv->display.wm.dsparb_lock); Can we do this in i9xx_wm_init() instead? > > i915_memcpy_init_early(dev_priv); > intel_runtime_pm_init_early(&dev_priv->runtime_pm); -- Jani Nikula, Intel Open Source Graphics Center
