From bdcdb913c2d36447ea49d33774e5d6093c55d6f7 Mon Sep 17 00:00:00 2001 From: Gustavo Sousa Date: Fri, 24 Jan 2025 16:12:34 -0300 Subject: [PATCH] drm/i915/dmc_wl: Do not check for DMC payload Enabling and disabling of DMC wakelock is already coupled with enabling and disabling of dynamic DC states, which already depend on the DMC being properly loaded. As such, we do not need to check if we already have a DMC payload parsed in __intel_dmc_wl_supported(). Furthermore, the presence of such a check causes inconsistencies in the refcount if the following sequence of events happen: 1. A call to one of the register accessors from intel_de.h is done before the DMC payload is parsed. That causes intel_dmc_wl_get() to be called. Suppose the register offset qualifies as needing the wakelock. In normal circumstances, the refcount would be incremented, but, because __intel_dmc_wl_supported() returns false, the refcount is untouched. 2. In a separate worker thread, the DMC firmware is parsed. Parsing of the DMC payload is finished before the corresponding intel_dmc_wl_put() from (1) is called. 3. When in the context of (1), intel_dmc_wl_put() gets called, now we have __intel_dmc_wl_supported() returning true and we hit the warning, because the code doesn't expect a zero refcount. Let's remove that check, since it is unnecessary and causes the inconsistency illustrated above. Reviewed-by: Krzysztof Karas Reviewed-by: Luca Coelho Link: https://patchwork.freedesktop.org/patch/msgid/20250124191250.56833-1-gustavo.sousa@intel.com Signed-off-by: Gustavo Sousa --- drivers/gpu/drm/i915/display/intel_dmc_wl.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_dmc_wl.c b/drivers/gpu/drm/i915/display/intel_dmc_wl.c index 86ba159b683c7..7e2ce0c2f6c39 100644 --- a/drivers/gpu/drm/i915/display/intel_dmc_wl.c +++ b/drivers/gpu/drm/i915/display/intel_dmc_wl.c @@ -10,7 +10,6 @@ #include "i915_drv.h" #include "i915_reg.h" #include "intel_de.h" -#include "intel_dmc.h" #include "intel_dmc_regs.h" #include "intel_dmc_wl.h" @@ -283,7 +282,7 @@ static bool intel_dmc_wl_check_range(struct intel_display *display, static bool __intel_dmc_wl_supported(struct intel_display *display) { - return display->params.enable_dmc_wl && intel_dmc_has_payload(display); + return display->params.enable_dmc_wl; } static void intel_dmc_wl_sanitize_param(struct intel_display *display) -- 2.39.5