drm/rockchip: dsi: Force synchronous probe

BugLink: https://bugs.launchpad.net/bugs/1998843
commit 81e592f86f7afdb76d655e7fbd7803d7b8f985d8 upstream.

We can't safely probe a dual-DSI display asynchronously
(driver_async_probe='*' or driver_async_probe='dw-mipi-dsi-rockchip'
cmdline), because dw_mipi_dsi_rockchip_find_second() pokes one DSI
device's drvdata from the other device without any locking.

Request synchronous probe, at least until this driver learns some
appropriate locking for dual-DSI initialization.

Cc: <stable@vger.kernel.org>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20221019170255.2.I6b985b0ca372b7e35c6d9ea970b24bcb262d4fc1@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
index 386dbba864b6763af4a063e4d83ef06198e51756..1129f98fe7f94eabefddc571afb5fa52c5419850 100644 (file)
--- a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
@@ -1638,5 +1638,11 @@ struct platform_driver dw_mipi_dsi_rockchip_driver = {
                .of_match_table = dw_mipi_dsi_rockchip_dt_ids,
                .pm     = &dw_mipi_dsi_rockchip_pm_ops,
                .name   = "dw-mipi-dsi-rockchip",
+               /*
+                * For dual-DSI display, one DSI pokes at the other DSI's
+                * drvdata in dw_mipi_dsi_rockchip_find_second(). This is not
+                * safe for asynchronous probe.
+                */
+               .probe_type = PROBE_FORCE_SYNCHRONOUS,
        },
 };