Re: [PATCH 20/25] drm/i915/ltphy: Define the LT Phy state compare function

[Murthy, Arun R]

On 15-10-2025 09:38, Suraj Kandpal wrote:

Define function to compare the state and if mismatch is detected
dump both the states.

Signed-off-by: Suraj Kandpal <suraj.kand...@intel.com>
---

Reviewed-by: Arun R Murthy <arun.r.mur...@intel.com>

Thanks and Regards,
Arun R Murthy
--------------------

  drivers/gpu/drm/i915/display/intel_display.c | 33 +++++++++++++++++++-
  drivers/gpu/drm/i915/display/intel_lt_phy.c  | 30 ++++++++++++++++++
  drivers/gpu/drm/i915/display/intel_lt_phy.h  |  6 ++++
  3 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c 
b/drivers/gpu/drm/i915/display/intel_display.c
index d5b2612d4ec2..b05f70582788 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -99,6 +99,7 @@
  #include "intel_hdmi.h"
  #include "intel_hotplug.h"
  #include "intel_link_bw.h"
+#include "intel_lt_phy.h"
  #include "intel_lvds.h"
  #include "intel_lvds_regs.h"
  #include "intel_modeset_setup.h"
@@ -4963,6 +4964,24 @@ static bool allow_vblank_delay_fastset(const struct 
intel_crtc_state *old_crtc_s
                !intel_crtc_has_type(old_crtc_state, INTEL_OUTPUT_DSI);
  }

+static void

+pipe_config_lt_phy_pll_mismatch(struct drm_printer *p, bool fastset,
+                               const struct intel_crtc *crtc,
+                               const char *name,
+                               const struct intel_lt_phy_pll_state *a,
+                               const struct intel_lt_phy_pll_state *b)
+{
+       struct intel_display *display = to_intel_display(crtc);
+       char *chipname = "LTPHY";
+
+       pipe_config_mismatch(p, fastset, crtc, name, chipname);
+
+       drm_printf(p, "expected:\n");
+       intel_lt_phy_dump_hw_state(display, a);
+       drm_printf(p, "found:\n");
+       intel_lt_phy_dump_hw_state(display, b);
+}
+
  bool
  intel_pipe_config_compare(const struct intel_crtc_state *current_config,
                          const struct intel_crtc_state *pipe_config,
@@ -5087,6 +5106,16 @@ intel_pipe_config_compare(const struct intel_crtc_state 
*current_config,
        } \
  } while (0)

+#define PIPE_CONF_CHECK_PLL_LT(name) do { \

+       if (!intel_lt_phy_pll_compare_hw_state(&current_config->name, \
+                                              &pipe_config->name)) { \
+               pipe_config_lt_phy_pll_mismatch(&p, fastset, crtc, 
__stringify(name), \
+                                               &current_config->name, \
+                                               &pipe_config->name); \
+               ret = false; \
+       } \
+} while (0)
+
  #define PIPE_CONF_CHECK_TIMINGS(name) do {     \
        PIPE_CONF_CHECK_I(name.crtc_hdisplay); \
        PIPE_CONF_CHECK_I(name.crtc_htotal); \
@@ -5311,7 +5340,9 @@ intel_pipe_config_compare(const struct intel_crtc_state 
*current_config,
                PIPE_CONF_CHECK_PLL(dpll_hw_state);

/* FIXME convert MTL+ platforms over to dpll_mgr */

-       if (DISPLAY_VER(display) >= 14)
+       if (HAS_LT_PHY(display))
+               PIPE_CONF_CHECK_PLL_LT(dpll_hw_state.ltpll);
+       else if (DISPLAY_VER(display) >= 14)
                PIPE_CONF_CHECK_PLL_CX0(dpll_hw_state.cx0pll);

PIPE_CONF_CHECK_X(dsi_pll.ctrl);

diff --git a/drivers/gpu/drm/i915/display/intel_lt_phy.c 
b/drivers/gpu/drm/i915/display/intel_lt_phy.c
index f1e41f009bb5..0be4aad0efcc 100644
--- a/drivers/gpu/drm/i915/display/intel_lt_phy.c
+++ b/drivers/gpu/drm/i915/display/intel_lt_phy.c
@@ -1843,6 +1843,36 @@ void intel_lt_phy_set_signal_levels(struct intel_encoder 
*encoder,
        intel_lt_phy_transaction_end(encoder, wakeref);
  }

+void intel_lt_phy_dump_hw_state(struct intel_display *display,

+                               const struct intel_lt_phy_pll_state *hw_state)
+{
+       int i, j;
+
+       drm_dbg_kms(display->drm, "lt_phy_pll_hw_state:\n");
+       for (i = 0; i < 3; i++) {
+               drm_dbg_kms(display->drm, "config[%d] = 0x%.4x,\n",
+                           i, hw_state->config[i]);
+       }
+
+       for (i = 0; i <= 12; i++)
+               for (j = 3; j >= 0; j--)
+                       drm_dbg_kms(display->drm, "vdr_data[%d][%d] = 
0x%.4x,\n",
+                                   i, j, hw_state->data[i][j]);
+}
+
+bool
+intel_lt_phy_pll_compare_hw_state(const struct intel_lt_phy_pll_state *a,
+                                 const struct intel_lt_phy_pll_state *b)
+{
+       if (memcmp(&a->config, &b->config, sizeof(a->config)) != 0)
+               return false;
+
+       if (memcmp(&a->data, &b->data, sizeof(a->data)) != 0)
+               return false;
+
+       return true;
+}
+
  void intel_xe3plpd_pll_enable(struct intel_encoder *encoder,
                              const struct intel_crtc_state *crtc_state)
  {
diff --git a/drivers/gpu/drm/i915/display/intel_lt_phy.h 
b/drivers/gpu/drm/i915/display/intel_lt_phy.h
index 6e67ae78801c..e93e5becc316 100644
--- a/drivers/gpu/drm/i915/display/intel_lt_phy.h
+++ b/drivers/gpu/drm/i915/display/intel_lt_phy.h
@@ -8,6 +8,7 @@

#include <linux/types.h> +struct intel_display;

  struct intel_encoder;
  struct intel_crtc_state;
  struct intel_lt_phy_pll_state;
@@ -22,6 +23,11 @@ int intel_lt_phy_calc_port_clock(struct intel_encoder 
*encoder,
                                 const struct intel_crtc_state *crtc_state);
  void intel_lt_phy_set_signal_levels(struct intel_encoder *encoder,
                                    const struct intel_crtc_state *crtc_state);
+void intel_lt_phy_dump_hw_state(struct intel_display *display,
+                               const struct intel_lt_phy_pll_state *hw_state);
+bool
+intel_lt_phy_pll_compare_hw_state(const struct intel_lt_phy_pll_state *a,
+                                 const struct intel_lt_phy_pll_state *b);
  void intel_xe3plpd_pll_enable(struct intel_encoder *encoder,
                              const struct intel_crtc_state *crtc_state);
  void intel_xe3plpd_pll_disable(struct intel_encoder *encoder);