From mboxrd@z Thu Jan 1 00:00:00 1970 From: mark.yao@rock-chips.com (Mark Yao) Date: Thu, 13 Oct 2016 09:50:38 +0800 Subject: [PATCH v2] drm/bridge: analogix: protect power when get_modes or detect In-Reply-To: <1476266442-29803-1-git-send-email-mark.yao@rock-chips.com> References: <1476266442-29803-1-git-send-email-mark.yao@rock-chips.com> Message-ID: <1476323438-8435-1-git-send-email-mark.yao@rock-chips.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org The drm callback ->detect and ->get_modes seems is not power safe, they may be called when device is power off, do register access on detect or get_modes will cause system die. Here is the path call ->detect before analogix_dp power on [] analogix_dp_detect+0x44/0xdc [] drm_helper_probe_single_connector_modes_merge_bits+0xe8/0x41c [] drm_helper_probe_single_connector_modes+0x10/0x18 [] drm_mode_getconnector+0xf4/0x304 [] drm_ioctl+0x23c/0x390 [] do_vfs_ioctl+0x4b8/0x58c [] SyS_ioctl+0x60/0x88 Cc: Inki Dae Cc: Sean Paul Cc: Gustavo Padovan Cc: "Ville Syrj?l?" Signed-off-by: Mark Yao --- Changes in v2: - remove sub device power on/off callback, use pm_runtime_get/put is enough to fix my problem, so will can avoid race to dpms. drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c index efac8ab..ff2d328 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -1062,11 +1062,15 @@ int analogix_dp_get_modes(struct drm_connector *connector) return 0; } + pm_runtime_get_sync(dp->dev); + if (analogix_dp_handle_edid(dp) == 0) { drm_mode_connector_update_edid_property(&dp->connector, edid); num_modes += drm_add_edid_modes(&dp->connector, edid); } + pm_runtime_put(dp->dev); + if (dp->plat_data->panel) num_modes += drm_panel_get_modes(dp->plat_data->panel); @@ -1106,9 +1110,13 @@ analogix_dp_detect(struct drm_connector *connector, bool force) return connector_status_disconnected; } + pm_runtime_get_sync(dp->dev); + if (!analogix_dp_detect_hpd(dp)) status = connector_status_connected; + pm_runtime_put(dp->dev); + ret = analogix_dp_prepare_panel(dp, false, false); if (ret) DRM_ERROR("Failed to unprepare panel (%d)\n", ret); -- 1.9.1