On Tue, 15 Apr 2025, Nemesa Garg <nemesa.g...@intel.com> wrote:
> Workaround recommend use polling method
> for pm_demand to finish as to avoid timeout.
>
> Signed-off-by: Nemesa Garg <nemesa.g...@intel.com>
> ---
> drivers/gpu/drm/i915/display/intel_pmdemand.c | 27 +++++++++++++++++--
> 1 file changed, 25 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_pmdemand.c
> b/drivers/gpu/drm/i915/display/intel_pmdemand.c
> index d22b5469672d..610d05b73b99 100644
> --- a/drivers/gpu/drm/i915/display/intel_pmdemand.c
> +++ b/drivers/gpu/drm/i915/display/intel_pmdemand.c
> @@ -478,6 +478,22 @@ static bool intel_pmdemand_req_complete(struct
> intel_display *display)
> XELPDP_PMDEMAND_REQ_ENABLE);
> }
>
> +static void intel_pmdemand_poll(struct intel_display *display)
> +{
> + const unsigned int timeout_ms = 10;
> + u32 status;
> + int ret;
> +
> + ret = intel_de_wait_custom(display, XELPDP_INITIATE_PMDEMAND_REQUEST(1),
> + XELPDP_PMDEMAND_REQ_ENABLE, 0,
> + 50, timeout_ms, &status);
> +
> + if (ret == -ETIMEDOUT)
> + drm_err(display->drm,
> + "timeout within %ums (status 0x%08x)\n",
> + timeout_ms, status);
Imagine seeing "timeout within 10ms" in dmesg.
Timeout of what?
> +}
> +
> static void intel_pmdemand_wait(struct intel_display *display)
> {
> if (!wait_event_timeout(display->pmdemand.waitqueue,
> @@ -508,7 +524,11 @@ void intel_pmdemand_program_dbuf(struct intel_display
> *display,
> intel_de_rmw(display, XELPDP_INITIATE_PMDEMAND_REQUEST(1), 0,
> XELPDP_PMDEMAND_REQ_ENABLE);
>
> - intel_pmdemand_wait(display);
> + /* Wa_14024400148 For lnl use polling method */
> + if (DISPLAY_VER(display) == 20)
> + intel_pmdemand_poll(display);
> + else
> + intel_pmdemand_wait(display);
Please just hide this within intel_pmdemand_wait() instead of
duplicating it everywhere.
>
> unlock:
> mutex_unlock(&display->pmdemand.lock);
> @@ -617,7 +637,10 @@ intel_pmdemand_program_params(struct intel_display
> *display,
> intel_de_rmw(display, XELPDP_INITIATE_PMDEMAND_REQUEST(1), 0,
> XELPDP_PMDEMAND_REQ_ENABLE);
>
> - intel_pmdemand_wait(display);
> + if (DISPLAY_VER(display) == 20)
> + intel_pmdemand_poll(display);
> + else
> + intel_pmdemand_wait(display);
>
> unlock:
> mutex_unlock(&display->pmdemand.lock);
--
Jani Nikula, Intel
