[Intel-gfx] [PATCH v5 2/2] drm/i915: State readout and cross-checking for dp_m2_n2
Daniel Vetter
daniel at ffwll.ch
Tue Jun 17 18:42:40 CEST 2014
On Tue, Jun 17, 2014 at 05:52:24PM +0300, Jani Nikula wrote:
> On Mon, 16 Jun 2014, Vandana Kannan <vandana.kannan at intel.com> wrote:
> > On Jun-13-2014 7:42 PM, Jani Nikula wrote:
> >> On Thu, 22 May 2014, Vandana Kannan <vandana.kannan at intel.com> wrote:
> >>> Adding relevant read out comparison code, in check_crtc_state, for the new
> >>> member of crtc_config, dp_m2_n2, which was introduced to store link_m_n
> >>> values for a DP downclock mode (if available). Suggested by Daniel.
> >>>
> >>> v2: Changed patch title.
> >>> Daniel's review comments incorporated.
> >>> Added relevant state readout code for M2_N2. dp_m2_n2 comparison to be done
> >>> only when high RR is not in use (This is because alternate m_n register
> >>> programming will be done only when low RR is being used).
> >>>
> >>> v3: Modified call to get_m2_n2 which had dp_m_n as param by mistake.
> >>> Compare dp_m_n and dp_m2_n2 for gen 7 and below. compare the structures
> >>> based on DRRS state for gen 8 and above.
> >>> Save and restore M2 N2 registers for gen 7 and below
> >>>
> >>> v4: For Gen>=8, check M_N registers against dp_m_n and dp_m2_n2 as there is
> >>> only one set of M_N registers
> >>>
> >>> v5: Removed the chunk which saves and restores M2_N2 registers. Modified
> >>> get_m_n() to get M2_N2 registers as well. Modified the macro which compares
> >>> hw.dp_m_n against sw.dp_m2_n2/sw.dp_m_n for gen > 8.
> >>>
> >>> Signed-off-by: Vandana Kannan <vandana.kannan at intel.com>
> >>> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> >>> ---
> >>> drivers/gpu/drm/i915/intel_display.c | 68 +++++++++++++++++++++++++++++++-----
> >>> 1 file changed, 60 insertions(+), 8 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> >>> index cf3ad87..d593897 100644
> >>> --- a/drivers/gpu/drm/i915/intel_display.c
> >>> +++ b/drivers/gpu/drm/i915/intel_display.c
> >>> @@ -6945,7 +6945,8 @@ static void intel_pch_transcoder_get_m_n(struct intel_crtc *crtc,
> >>>
> >>> static void intel_cpu_transcoder_get_m_n(struct intel_crtc *crtc,
> >>> enum transcoder transcoder,
> >>> - struct intel_link_m_n *m_n)
> >>> + struct intel_link_m_n *m_n,
> >>> + struct intel_link_m_n *m2_n2)
> >>> {
> >>> struct drm_device *dev = crtc->base.dev;
> >>> struct drm_i915_private *dev_priv = dev->dev_private;
> >>> @@ -6959,6 +6960,15 @@ static void intel_cpu_transcoder_get_m_n(struct intel_crtc *crtc,
> >>> m_n->gmch_n = I915_READ(PIPE_DATA_N1(transcoder));
> >>> m_n->tu = ((I915_READ(PIPE_DATA_M1(transcoder))
> >>> & TU_SIZE_MASK) >> TU_SIZE_SHIFT) + 1;
> >>> + if (m2_n2 && INTEL_INFO(dev)->gen < 8) {
> >>> + m2_n2->link_m = I915_READ(PIPE_LINK_M2(transcoder));
> >>> + m2_n2->link_n = I915_READ(PIPE_LINK_N2(transcoder));
> >>> + m2_n2->gmch_m = I915_READ(PIPE_DATA_M2(transcoder))
> >>> + & ~TU_SIZE_MASK;
> >>> + m2_n2->gmch_n = I915_READ(PIPE_DATA_N2(transcoder));
> >>> + m2_n2->tu = ((I915_READ(PIPE_DATA_M2(transcoder))
> >>> + & TU_SIZE_MASK) >> TU_SIZE_SHIFT) + 1;
> >>> + }
> >>> } else {
> >>> m_n->link_m = I915_READ(PIPE_LINK_M_G4X(pipe));
> >>> m_n->link_n = I915_READ(PIPE_LINK_N_G4X(pipe));
> >>> @@ -6977,14 +6987,15 @@ void intel_dp_get_m_n(struct intel_crtc *crtc,
> >>> intel_pch_transcoder_get_m_n(crtc, &pipe_config->dp_m_n);
> >>> else
> >>> intel_cpu_transcoder_get_m_n(crtc, pipe_config->cpu_transcoder,
> >>> - &pipe_config->dp_m_n);
> >>> + &pipe_config->dp_m_n,
> >>> + &pipe_config->dp_m2_n2);
> >>> }
> >>>
> >>> static void ironlake_get_fdi_m_n_config(struct intel_crtc *crtc,
> >>> struct intel_crtc_config *pipe_config)
> >>> {
> >>> intel_cpu_transcoder_get_m_n(crtc, pipe_config->cpu_transcoder,
> >>> - &pipe_config->fdi_m_n);
> >>> + &pipe_config->fdi_m_n, NULL);
> >>> }
> >>>
> >>> static void ironlake_get_pfit_config(struct intel_crtc *crtc,
> >>> @@ -9485,6 +9496,15 @@ static void intel_dump_pipe_config(struct intel_crtc *crtc,
> >>> pipe_config->dp_m_n.gmch_m, pipe_config->dp_m_n.gmch_n,
> >>> pipe_config->dp_m_n.link_m, pipe_config->dp_m_n.link_n,
> >>> pipe_config->dp_m_n.tu);
> >>> +
> >>> + DRM_DEBUG_KMS("dp: %i, gmch_m2: %u, gmch_n2: %u, link_m2: %u, link_n2: %u, tu2: %u\n",
> >>> + pipe_config->has_dp_encoder,
> >>> + pipe_config->dp_m2_n2.gmch_m,
> >>> + pipe_config->dp_m2_n2.gmch_n,
> >>> + pipe_config->dp_m2_n2.link_m,
> >>> + pipe_config->dp_m2_n2.link_n,
> >>> + pipe_config->dp_m2_n2.tu);
> >>> +
> >>> DRM_DEBUG_KMS("requested mode:\n");
> >>> drm_mode_debug_printmodeline(&pipe_config->requested_mode);
> >>> DRM_DEBUG_KMS("adjusted mode:\n");
> >>> @@ -9867,6 +9887,22 @@ intel_pipe_config_compare(struct drm_device *dev,
> >>> return false; \
> >>> }
> >>>
> >>> +/* This is required for BDW+ where there is only one set of registers for
> >>> + * switching between high and low RR.
> >>> + * This macro can be used whenever a comparison has to be made between one
> >>> + * hw state and multiple sw state variables.
> >>> + */
> >>> +#define PIPE_CONF_CHECK_I_ALT(name, alt_name) \
> >>> + if ((current_config->name != pipe_config->name) && \
> >>> + (current_config->alt_name != pipe_config->name)) { \
> >>> + DRM_ERROR("mismatch in " #name " " \
> >>> + "(expected %i or %i, found %i)\n", \
> >>> + current_config->name, \
> >>> + current_config->alt_name, \
> >>> + pipe_config->name); \
> >>> + return false; \
> >>> + }
> >>> +
> >>> #define PIPE_CONF_CHECK_FLAGS(name, mask) \
> >>> if ((current_config->name ^ pipe_config->name) & (mask)) { \
> >>> DRM_ERROR("mismatch in " #name "(" #mask ") " \
> >>> @@ -9899,11 +9935,26 @@ intel_pipe_config_compare(struct drm_device *dev,
> >>> PIPE_CONF_CHECK_I(fdi_m_n.tu);
> >>>
> >>> PIPE_CONF_CHECK_I(has_dp_encoder);
> >>> - PIPE_CONF_CHECK_I(dp_m_n.gmch_m);
> >>> - PIPE_CONF_CHECK_I(dp_m_n.gmch_n);
> >>> - PIPE_CONF_CHECK_I(dp_m_n.link_m);
> >>> - PIPE_CONF_CHECK_I(dp_m_n.link_n);
> >>> - PIPE_CONF_CHECK_I(dp_m_n.tu);
> >>> +
> >>> + if (INTEL_INFO(dev)->gen < 8) {
> >>> + PIPE_CONF_CHECK_I(dp_m_n.gmch_m);
> >>> + PIPE_CONF_CHECK_I(dp_m_n.gmch_n);
> >>> + PIPE_CONF_CHECK_I(dp_m_n.link_m);
> >>> + PIPE_CONF_CHECK_I(dp_m_n.link_n);
> >>> + PIPE_CONF_CHECK_I(dp_m_n.tu);
> >>> +
> >>> + PIPE_CONF_CHECK_I(dp_m2_n2.gmch_m);
> >>> + PIPE_CONF_CHECK_I(dp_m2_n2.gmch_n);
> >>> + PIPE_CONF_CHECK_I(dp_m2_n2.link_m);
> >>> + PIPE_CONF_CHECK_I(dp_m2_n2.link_n);
> >>> + PIPE_CONF_CHECK_I(dp_m2_n2.tu);
> >>> + } else {
> >>> + PIPE_CONF_CHECK_I_ALT(dp_m_n.gmch_m, dp_m2_n2.gmch_m);
> >>> + PIPE_CONF_CHECK_I_ALT(dp_m_n.gmch_n, dp_m2_n2.gmch_n);
> >>> + PIPE_CONF_CHECK_I_ALT(dp_m_n.link_m, dp_m2_n2.link_m);
> >>> + PIPE_CONF_CHECK_I_ALT(dp_m_n.link_n, dp_m2_n2.link_n);
> >>> + PIPE_CONF_CHECK_I_ALT(dp_m_n.tu, dp_m2_n2.tu);
> >>
> >> If there's no downclock mode (e.g. because it's not eDP), this now
> >> accepts register value 0 as okay for each state check. That's not cool.
> >>
> >> Perhaps drrs state should be part of pipe config.
> >>
> >> BR,
> >> Jani.
> >>
> > Ok, shall I go ahead with the following approach?
> >
> > pipe_config{
> > drrs_state;
> > }
> >
> > in pipe_config_compare() {
> > if gen < 8 {
> > compare dp_m1_n1
> > if drrs_state == seamless
> > compare hw.dp_m2_n2 and sw.dp_m2_n2
> > /* this drrs_state would be set only in edp_init_connector and only when
> > a downclock_mode is found */
> > }
> > else
> > compare hw.dp_m_n and sw.dp_m_n or sw.dp_m2_n2
> > }
> >
> > drrs_state is stored in vbt struct and intel_dp as of now. some changes
> > would be required around this to avoid saving this state at a third
> > place (pipe_config).
> > option 1. move drrs_state from intel_dp to dev_priv.
> > option 2. move drrs_state from intel_dp to pipe_config.
> >
> > with the above changes, the patches accessing intel_dp->drrs_state would
> > require changes.
> >
> > Please let me know your inputs on this.
>
> Daniel, any further thoughts on this? What fits best with future work?
> Or go ahead with the patch as-is, even though it has the corner case?
I think we should have a flag that says whether the 2nd set of regs is
valid, then only use those if that's set. So amounts to adding a static
copy to pipe_config, e.g. config.has_drrs -> 2nd set of values is valid.
Or we just compare against 0 and don't use them if they're all 0 since
that's just not a valid m/n setting.
Future plans for drrs are more about tracking and will require moving
things around in general all over the place. Imo no concern for this patch
here.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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