On Wed, Mar 12, 2025 at 08:13:10PM +0530, Mohammed Thasleem wrote:
> Starting from MTL we don't have a platform agnostic way to validate
> DC6 state due to dc6 counter has been removed to validate DC state.
>
> The goal is to validate that the display HW can reach the DC6 power
> state. There is no HW DC6 residency counter (and there wasn't such
> a counter earlier either), so an alternative way is required. According
> to the HW team the display driver has programmed everything correctly in
> order to allow the DC6 power state if the DC5 power state is reached
> (indicated by the HW DC5 residency counter incrementing) and DC6 is
> enabled by the driver.
>
> Driver could take a snapshot of the DC5 residency counter right
> after it enables DC6 (dc5_residency_start) and increment the SW
> DC6 residency counter right before it disables DC6 or when user space
> reads the DC6 counter. So the driver would update the counter at these
> two points in the following way:
> dc6_residency_counter += dc5_current_count - dc5_start_count
>
> v2: Update the discription. (Imre)
> Read dc5 count during dc6 enable and disable then and update
> dc6 residency counter. (Imre)
> Remove variable from dmc structure. (Jani)
> Updated the subject title.
> v3: Add i915_power_domains lock to updated dc6 count in debugfs. (Imre)
> Use flags to check dc6 enable/disable states. (Imre)
> Move the display version check and counter read/update to
> a helper. (Imre)
> Resize the variable length. (Rodrigo)
> Use old dc6 debugfs entry for every platform. (Rodrigo)
> v4: Remove superfluous whitespace. (Jani)
> Read DMC registers in intel_dmc.c (Jani)
> Rename dc6_en_dis to dc6_enabled and change its type to bool. (Jani)
> Rename update_dc6_count and move it to intel_dmc.c (Jani)
> Rename dc6_en_dis to start_tracking. (Imre)
> Have lock for dc6 state read aswelll. (Imre)
> Keep the existing way print 'DC5 -> DC6 count' along with
> new 'DC6 Allowed Count' print. (Imre)
> Add counters in intel_dmc struct. (Imre)
> Have interface to return dc6 allowed count. (Imre)
> Rename dc6_count to dc6_allowed_count. (Rodrigo)
> v5: Rename counters and move in to dc6_allowed structure. (Imre)
> Order declaration lines in decreasing line length. (Imre)
> Update start_tacking logic. (Imre)
> Move get couner inside lock and DISPLAY_VER code to helper. (Imre)
>
> Signed-off-by: Mohammed Thasleem <mohammed.thasleem@xxxxxxxxx>
> ---
> .../i915/display/intel_display_power_well.c | 11 +++-
> drivers/gpu/drm/i915/display/intel_dmc.c | 54 +++++++++++++++++--
> drivers/gpu/drm/i915/display/intel_dmc.h | 1 +
> 3 files changed, 62 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_power_well.c b/drivers/gpu/drm/i915/display/intel_display_power_well.c
> index 8ec87ffd87d2..574352439573 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_power_well.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_power_well.c
> @@ -752,8 +752,9 @@ void gen9_sanitize_dc_state(struct intel_display *display)
> void gen9_set_dc_state(struct intel_display *display, u32 state)
> {
> struct i915_power_domains *power_domains = &display->power.domains;
> - u32 val;
> + bool dc6_was_enabled, enable_dc6;
> u32 mask;
> + u32 val;
>
> if (!HAS_DISPLAY(display))
> return;
> @@ -772,11 +773,19 @@ void gen9_set_dc_state(struct intel_display *display, u32 state)
> drm_err(display->drm, "DC state mismatch (0x%x -> 0x%x)\n",
> power_domains->dc_state, val & mask);
>
> + enable_dc6 = state & DC_STATE_EN_UPTO_DC6;
> + dc6_was_enabled = val & DC_STATE_EN_UPTO_DC6;
> + if (!dc6_was_enabled && enable_dc6)
> + intel_dmc_update_dc6_allowed_count(display, true);
> +
> val &= ~mask;
> val |= state;
>
> gen9_write_dc_state(display, val);
>
> + if (!enable_dc6 && dc6_was_enabled)
> + intel_dmc_update_dc6_allowed_count(display, false);
> +
> power_domains->dc_state = val & mask;
> }
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c b/drivers/gpu/drm/i915/display/intel_dmc.c
> index fa6944e55d95..95abeec0586a 100644
> --- a/drivers/gpu/drm/i915/display/intel_dmc.c
> +++ b/drivers/gpu/drm/i915/display/intel_dmc.c
> @@ -28,6 +28,7 @@
> #include "i915_drv.h"
> #include "i915_reg.h"
> #include "intel_de.h"
> +#include "intel_display_power_well.h"
> #include "intel_dmc.h"
> #include "intel_dmc_regs.h"
> #include "intel_step.h"
> @@ -57,6 +58,10 @@ struct intel_dmc {
> const char *fw_path;
> u32 max_fw_size; /* bytes */
> u32 version;
> + struct {
> + u32 dc5_start;
> + u32 count;
> + } dc6_allowed;
> struct dmc_fw_info {
> u32 mmio_count;
> i915_reg_t mmioaddr[20];
> @@ -1232,6 +1237,43 @@ void intel_dmc_snapshot_print(const struct intel_dmc_snapshot *snapshot, struct
> DMC_VERSION_MINOR(snapshot->version));
> }
>
> +void intel_dmc_update_dc6_allowed_count(struct intel_display *display,
> + bool start_tracking)
> +{
> + struct intel_dmc *dmc = display_to_dmc(display);
> + u32 dc5_cur_count;
> +
> + if (DISPLAY_VER(dmc->display) < 14)
> + return;
> +
> + dc5_cur_count = intel_de_read(dmc->display, DG1_DMC_DEBUG_DC5_COUNT);
> +
> + if (!start_tracking)
> + dmc->dc6_allowed.count += dc5_cur_count - dmc->dc6_allowed.dc5_start;
> +
> + dmc->dc6_allowed.dc5_start = dc5_cur_count;
> +}
> +
> +static u32 intel_dmc_get_dc6_allowed_count(struct intel_display *display, u32 *count)
The return type isn't compatible with the -ENODEV returned value. I'd
just return a bool, since the reason for an error is always the same.
> +{
> + struct i915_power_domains *power_domains = &display->power.domains;
> + struct intel_dmc *dmc = display_to_dmc(display);
> +
> + if (DISPLAY_VER(display) < 14)
> + return -ENODEV;
> +
> + mutex_lock(&power_domains->lock);
> + bool dc6_enabled = DC_STATE_EN_UPTO_DC6 &
> + intel_de_read(display, DC_STATE_EN);
> + if (dc6_enabled)
> + intel_dmc_update_dc6_allowed_count(display, false);
> +
> + *count = dmc->dc6_allowed.count;
> + mutex_unlock(&power_domains->lock);
> +
> + return 0;
> +}
> +
> static int intel_dmc_debugfs_status_show(struct seq_file *m, void *unused)
> {
> struct intel_display *display = m->private;
> @@ -1239,6 +1281,7 @@ static int intel_dmc_debugfs_status_show(struct seq_file *m, void *unused)
> struct intel_dmc *dmc = display_to_dmc(display);
> intel_wakeref_t wakeref;
> i915_reg_t dc5_reg, dc6_reg = INVALID_MMIO_REG;
> + u32 dc6_allowed_count;
>
> if (!HAS_DMC(display))
> return -ENODEV;
> @@ -1287,9 +1330,14 @@ static int intel_dmc_debugfs_status_show(struct seq_file *m, void *unused)
> }
>
> seq_printf(m, "DC3 -> DC5 count: %d\n", intel_de_read(display, dc5_reg));
> - if (i915_mmio_reg_valid(dc6_reg))
> - seq_printf(m, "DC5 -> DC6 count: %d\n",
> - intel_de_read(display, dc6_reg));
> +
> + if (intel_dmc_get_dc6_allowed_count(display, &dc6_allowed_count) == 0) {
> + seq_printf(m, "DC6 Allowed Count : %d\n", dc6_allowed_count);
"DC5 -> DC6 allowed count: %d\n" would align better with the other
entries printed.
> + } else {
> + if (i915_mmio_reg_valid(dc6_reg)) {
The above else/if could be combined to 'else if (i915_mmio_reg_valid(...))'
and the {} could be dropped from around both resultant if branches.
With the above fixed the patch looks ok to me:
Reviewed-by: Imre Deak <imre.deak@xxxxxxxxx>
> + seq_printf(m, "DC5 -> DC6 count: %d\n",
> + intel_de_read(display, dc6_reg)); }
> + }
>
> seq_printf(m, "program base: 0x%08x\n",
> intel_de_read(display, DMC_PROGRAM(dmc->dmc_info[DMC_FW_MAIN].start_mmioaddr, 0)));
> diff --git a/drivers/gpu/drm/i915/display/intel_dmc.h b/drivers/gpu/drm/i915/display/intel_dmc.h
> index 44cecef98e73..c78426eb4cd5 100644
> --- a/drivers/gpu/drm/i915/display/intel_dmc.h
> +++ b/drivers/gpu/drm/i915/display/intel_dmc.h
> @@ -26,6 +26,7 @@ void intel_dmc_debugfs_register(struct intel_display *display);
>
> struct intel_dmc_snapshot *intel_dmc_snapshot_capture(struct intel_display *display);
> void intel_dmc_snapshot_print(const struct intel_dmc_snapshot *snapshot, struct drm_printer *p);
> +void intel_dmc_update_dc6_allowed_count(struct intel_display *display, bool start_tracking);
>
> void assert_dmc_loaded(struct intel_display *display);
>
> --
> 2.43.0
>
