The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x fd2611c13f69cbbc6b81d9fc7502abf4f7031d21 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025063040-crablike-endorse-741f@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From fd2611c13f69cbbc6b81d9fc7502abf4f7031d21 Mon Sep 17 00:00:00 2001 From: Aradhya Bhatia a-bhatia1@ti.com Date: Sat, 29 Mar 2025 17:09:13 +0530 Subject: [PATCH] drm/bridge: cdns-dsi: Fix phy de-init and flag it so

The driver code doesn't have a Phy de-initialization path as yet, and so it does not clear the phy_initialized flag while suspending. This is a problem because after resume the driver looks at this flag to determine if a Phy re-initialization is required or not. It is in fact required because the hardware is resuming from a suspend, but the driver does not carry out any re-initialization causing the D-Phy to not work at all.

Call the counterparts of phy_init() and phy_power_on(), that are phy_exit() and phy_power_off(), from _bridge_post_disable(), and clear the flags so that the Phy can be initialized again when required.

Fixes: fced5a364dee ("drm/bridge: cdns: Convert to phy framework") Cc: stable@vger.kernel.org Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Reviewed-by: Tomi Valkeinen tomi.valkeinen@ideasonboard.com Tested-by: Tomi Valkeinen tomi.valkeinen@ideasonboard.com Signed-off-by: Aradhya Bhatia a-bhatia1@ti.com Signed-off-by: Aradhya Bhatia aradhya.bhatia@linux.dev Link: https://lore.kernel.org/r/20250329113925.68204-3-aradhya.bhatia@linux.dev Signed-off-by: Dmitry Baryshkov dmitry.baryshkov@oss.qualcomm.com

diff --git a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c index 1cfe17865b06..3b15528713fe 100644 --- a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c +++ b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c @@ -683,6 +683,11 @@ static void cdns_dsi_bridge_atomic_post_disable(struct drm_bridge *bridge, struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge); struct cdns_dsi *dsi = input_to_dsi(input);

+ dsi->phy_initialized = false; + dsi->link_initialized = false; + phy_power_off(dsi->dphy); + phy_exit(dsi->dphy); + pm_runtime_put(dsi->base.dev); }

@@ -1166,7 +1171,6 @@ static int __maybe_unused cdns_dsi_suspend(struct device *dev) clk_disable_unprepare(dsi->dsi_sys_clk); clk_disable_unprepare(dsi->dsi_p_clk); reset_control_assert(dsi->dsi_p_rst); - dsi->link_initialized = false; return 0; }