From 6b7cbdbe20b33943b86cb8d752ade6841e83fc42 Mon Sep 17 00:00:00 2001 From: Jonathan Cavitt Date: Thu, 8 Dec 2022 12:05:20 -0800 Subject: [PATCH] drm/i915/gsc: Disable GSC engine and power well if FW is not selected The GSC CS is only used for communicating with the GSC FW, so no need to initialize it if we're not going to use the FW. If we're not using neither the engine nor the microcontoller, then we can also disable the power well. IMPORTANT: lack of GSC FW breaks media C6 due to opposing requirements between CS setup and forcewake idleness. See in-code comment for detail. Signed-off-by: Jonathan Cavitt Signed-off-by: Daniele Ceraolo Spurio Cc: Matt Roper Cc: John C Harrison Cc: Rodrigo Vivi Cc: Vinay Belgaumkar Reviewed-by: Rodrigo Vivi Link: https://patchwork.freedesktop.org/patch/msgid/20221208200521.2928378-6-daniele.ceraolospurio@intel.com --- drivers/gpu/drm/i915/gt/intel_engine_cs.c | 18 ++++++++++++++++++ drivers/gpu/drm/i915/intel_uncore.c | 3 +++ 2 files changed, 21 insertions(+) diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c index f63829a..8ede489 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c @@ -892,6 +892,24 @@ static intel_engine_mask_t init_engine_mask(struct intel_gt *gt) engine_mask_apply_compute_fuses(gt); engine_mask_apply_copy_fuses(gt); + /* + * The only use of the GSC CS is to load and communicate with the GSC + * FW, so we have no use for it if we don't have the FW. + * + * IMPORTANT: in cases where we don't have the GSC FW, we have a + * catch-22 situation that breaks media C6 due to 2 requirements: + * 1) once turned on, the GSC power well will not go to sleep unless the + * GSC FW is loaded. + * 2) to enable idling (which is required for media C6) we need to + * initialize the IDLE_MSG register for the GSC CS and do at least 1 + * submission, which will wake up the GSC power well. + */ + if (__HAS_ENGINE(info->engine_mask, GSC0) && !intel_uc_wants_gsc_uc(>->uc)) { + drm_notice(>->i915->drm, + "No GSC FW selected, disabling GSC CS and media C6\n"); + info->engine_mask &= ~BIT(GSC0); + } + return info->engine_mask; } diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c index 6a4006d..25eac16 100644 --- a/drivers/gpu/drm/i915/intel_uncore.c +++ b/drivers/gpu/drm/i915/intel_uncore.c @@ -2700,6 +2700,9 @@ void intel_uncore_prune_engine_fw_domains(struct intel_uncore *uncore, if (fw_domains & BIT(domain_id)) fw_domain_fini(uncore, domain_id); } + + if ((fw_domains & BIT(FW_DOMAIN_ID_GSC)) && !HAS_ENGINE(gt, GSC0)) + fw_domain_fini(uncore, FW_DOMAIN_ID_GSC); } /* -- 2.7.4