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Currently almost all bridge drivers which implement hpd_enable / hpd_disable callbacks simply toggle the hardware registers generating the interrupt. However, as pointed out by Jonas Karlman and Sashiko bot, using those callbacks for enable_irq() / disable_irq() calls or scheduling and cancelling the work can cause a AB-BA deadlock (between hpd_mutex lock and the corresponding lock). Split the hpd_mutex into two locks: one simply making sure that hpd_cb / hpd_data are consistent and another one, hpd_state_mutex, making sure that concurrent drm_bridge_hpd_enable() / drm_bridge_hpd_disable() calls can't end up with inconsistency between hpd_cb/_data and bridge's internal state. Link: https://lore.kernel.org/dri-devel/9aa4bd35-bff6-4009-a959-ce31010c7b35@kwiboo.se Link: https://sashiko.dev/#/patchset/20260513-dp-connector-hpd-v2-0-42f757bfcbf9%40oss.qualcomm.com Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com> Link: https://patch.msgid.link/20260528-dp-connector-hpd-v3-1-d656eb1079b7@oss.qualcomm.com Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>