This is a note to let you know that I've just added the patch titled

drm/bridge: analogix dp: Fix runtime PM state in get_modes() callback

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: drm-bridge-analogix-dp-fix-runtime-pm-state-in-get_modes-callback.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 510353a63796d467b41237ab4f136136f68c297d Mon Sep 17 00:00:00 2001

From: Marek Szyprowski m.szyprowski@samsung.com Date: Tue, 21 Nov 2017 08:49:36 +0100 Subject: drm/bridge: analogix dp: Fix runtime PM state in get_modes() callback

From: Marek Szyprowski m.szyprowski@samsung.com

commit 510353a63796d467b41237ab4f136136f68c297d upstream.

get_modes() callback might be called asynchronously from the DRM core and it is not synchronized with bridge_enable(), which sets proper runtime PM state of the main DP device. Fix this by calling pm_runtime_get_sync() before calling drm_get_edid(), which in turn calls drm_dp_i2c_xfer() and analogix_dp_transfer() to ensure that main DP device is runtime active when doing any access to its registers.

This fixes the following kernel issue on Samsung Exynos5250 Snow board: Unhandled fault: imprecise external abort (0x406) at 0x00000000 pgd = c0004000 [00000000] *pgd=00000000 Internal error: : 406 [#1] PREEMPT SMP ARM Modules linked in: CPU: 0 PID: 62 Comm: kworker/0:2 Not tainted 4.13.0-rc2-00364-g4a97a3da420b #3357 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) Workqueue: events output_poll_execute task: edc14800 task.stack: edcb2000 PC is at analogix_dp_transfer+0x15c/0x2fc LR is at analogix_dp_transfer+0x134/0x2fc pc : [<c0468538>] lr : [<c0468510>] psr: 60000013 sp : edcb3be8 ip : 0000002a fp : 00000001 r10: 00000000 r9 : edcb3cd8 r8 : edcb3c40 r7 : 00000000 r6 : edd3b380 r5 : edd3b010 r4 : 00000064 r3 : 00000000 r2 : f0ad3000 r1 : edcb3c40 r0 : edd3b010 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none Control: 10c5387d Table: 4000406a DAC: 00000051 Process kworker/0:2 (pid: 62, stack limit = 0xedcb2210) Stack: (0xedcb3be8 to 0xedcb4000) [<c0468538>] (analogix_dp_transfer) from [<c0424ba4>] (drm_dp_i2c_do_msg+0x8c/0x2b4) [<c0424ba4>] (drm_dp_i2c_do_msg) from [<c0424e64>] (drm_dp_i2c_xfer+0x98/0x214) [<c0424e64>] (drm_dp_i2c_xfer) from [<c057b2d8>] (__i2c_transfer+0x140/0x29c) [<c057b2d8>] (__i2c_transfer) from [<c057b4a4>] (i2c_transfer+0x70/0xe4) [<c057b4a4>] (i2c_transfer) from [<c0441de4>] (drm_do_probe_ddc_edid+0xb4/0x114) [<c0441de4>] (drm_do_probe_ddc_edid) from [<c0441e5c>] (drm_probe_ddc+0x18/0x28) [<c0441e5c>] (drm_probe_ddc) from [<c0445728>] (drm_get_edid+0x124/0x2d4) [<c0445728>] (drm_get_edid) from [<c0465ea0>] (analogix_dp_get_modes+0x90/0x114) [<c0465ea0>] (analogix_dp_get_modes) from [<c0425e8c>] (drm_helper_probe_single_connector_modes+0x198/0x68c) [<c0425e8c>] (drm_helper_probe_single_connector_modes) from [<c04325d4>] (drm_setup_crtcs+0x1b4/0xd18) [<c04325d4>] (drm_setup_crtcs) from [<c04344a8>] (drm_fb_helper_hotplug_event+0x94/0xd0) [<c04344a8>] (drm_fb_helper_hotplug_event) from [<c0425a50>] (drm_kms_helper_hotplug_event+0x24/0x28) [<c0425a50>] (drm_kms_helper_hotplug_event) from [<c04263ec>] (output_poll_execute+0x6c/0x174) [<c04263ec>] (output_poll_execute) from [<c0136f18>] (process_one_work+0x188/0x3fc) [<c0136f18>] (process_one_work) from [<c01371f4>] (worker_thread+0x30/0x4b8) [<c01371f4>] (worker_thread) from [<c013daf8>] (kthread+0x128/0x164) [<c013daf8>] (kthread) from [<c0108510>] (ret_from_fork+0x14/0x24) Code: 0a000002 ea000009 e2544001 0a00004a (e59537c8) ---[ end trace cddc7919c79f7878 ]---

Reported-by: Misha Komarovskiy zombah@gmail.com Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

Signed-off-by: Archit Taneja architt@codeaurora.org Link: https://patchwork.freedesktop.org/patch/msgid/20171121074936.22520-1-m.szypr...

--- drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 2 ++ 1 file changed, 2 insertions(+)

--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -946,7 +946,9 @@ static int analogix_dp_get_modes(struct return 0; }

+ pm_runtime_get_sync(dp->dev); edid = drm_get_edid(connector, &dp->aux.ddc); + pm_runtime_put(dp->dev); if (edid) { drm_mode_connector_update_edid_property(&dp->connector, edid);

Patches currently in stable-queue which might be from m.szyprowski@samsung.com are

queue-4.14/drm-bridge-analogix-dp-fix-runtime-pm-state-in-get_modes-callback.patch queue-4.14/drm-exynos-gem-drop-noncontig-flag-for-buffers-allocated-without-iommu.patch