Re: Patch "drm: zynqmp_dpsub: Always register bridge" has been added to the 6.9-stable tree

[Sean Anderson <sean.anderson@linux.dev>]

Hi Sasha,

Please also pick [1] when it is applied.

--Sean

[1] https://lore.kernel.org/all/974d1b062d7c61ee6db00d16fa7c69aa1218ee02.1716198025.git.christophe.jaillet@wanadoo.fr/

On 6/3/24 07:46, Sasha Levin wrote:
> This is a note to let you know that I've just added the patch titled
> 
>     drm: zynqmp_dpsub: Always register bridge
> 
> to the 6.9-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> 
> The filename of the patch is:
>      drm-zynqmp_dpsub-always-register-bridge.patch
> and it can be found in the queue-6.9 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.
> 
> 
> 
> commit d6817dc61b3b6a1e4f098b25109e7f2ecaaf0ee8
> Author: Sean Anderson <sean.anderson@linux.dev>
> Date:   Fri Mar 8 15:47:41 2024 -0500
> 
>     drm: zynqmp_dpsub: Always register bridge
>     
>     [ Upstream commit be3f3042391d061cfca2bd22630e0d101acea5fc ]
>     
>     We must always register the DRM bridge, since zynqmp_dp_hpd_work_func
>     calls drm_bridge_hpd_notify, which in turn expects hpd_mutex to be
>     initialized. We do this before zynqmp_dpsub_drm_init since that calls
>     drm_bridge_attach. This fixes the following lockdep warning:
>     
>     [   19.217084] ------------[ cut here ]------------
>     [   19.227530] DEBUG_LOCKS_WARN_ON(lock->magic != lock)
>     [   19.227768] WARNING: CPU: 0 PID: 140 at kernel/locking/mutex.c:582 __mutex_lock+0x4bc/0x550
>     [   19.241696] Modules linked in:
>     [   19.244937] CPU: 0 PID: 140 Comm: kworker/0:4 Not tainted 6.6.20+ #96
>     [   19.252046] Hardware name: xlnx,zynqmp (DT)
>     [   19.256421] Workqueue: events zynqmp_dp_hpd_work_func
>     [   19.261795] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>     [   19.269104] pc : __mutex_lock+0x4bc/0x550
>     [   19.273364] lr : __mutex_lock+0x4bc/0x550
>     [   19.277592] sp : ffffffc085c5bbe0
>     [   19.281066] x29: ffffffc085c5bbe0 x28: 0000000000000000 x27: ffffff88009417f8
>     [   19.288624] x26: ffffff8800941788 x25: ffffff8800020008 x24: ffffffc082aa3000
>     [   19.296227] x23: ffffffc080d90e3c x22: 0000000000000002 x21: 0000000000000000
>     [   19.303744] x20: 0000000000000000 x19: ffffff88002f5210 x18: 0000000000000000
>     [   19.311295] x17: 6c707369642e3030 x16: 3030613464662072 x15: 0720072007200720
>     [   19.318922] x14: 0000000000000000 x13: 284e4f5f4e524157 x12: 0000000000000001
>     [   19.326442] x11: 0001ffc085c5b940 x10: 0001ff88003f388b x9 : 0001ff88003f3888
>     [   19.334003] x8 : 0001ff88003f3888 x7 : 0000000000000000 x6 : 0000000000000000
>     [   19.341537] x5 : 0000000000000000 x4 : 0000000000001668 x3 : 0000000000000000
>     [   19.349054] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffffff88003f3880
>     [   19.356581] Call trace:
>     [   19.359160]  __mutex_lock+0x4bc/0x550
>     [   19.363032]  mutex_lock_nested+0x24/0x30
>     [   19.367187]  drm_bridge_hpd_notify+0x2c/0x6c
>     [   19.371698]  zynqmp_dp_hpd_work_func+0x44/0x54
>     [   19.376364]  process_one_work+0x3ac/0x988
>     [   19.380660]  worker_thread+0x398/0x694
>     [   19.384736]  kthread+0x1bc/0x1c0
>     [   19.388241]  ret_from_fork+0x10/0x20
>     [   19.392031] irq event stamp: 183
>     [   19.395450] hardirqs last  enabled at (183): [<ffffffc0800b9278>] finish_task_switch.isra.0+0xa8/0x2d4
>     [   19.405140] hardirqs last disabled at (182): [<ffffffc081ad3754>] __schedule+0x714/0xd04
>     [   19.413612] softirqs last  enabled at (114): [<ffffffc080133de8>] srcu_invoke_callbacks+0x158/0x23c
>     [   19.423128] softirqs last disabled at (110): [<ffffffc080133de8>] srcu_invoke_callbacks+0x158/0x23c
>     [   19.432614] ---[ end trace 0000000000000000 ]---
>     
>     Fixes: eb2d64bfcc17 ("drm: xlnx: zynqmp_dpsub: Report HPD through the bridge")
>     Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
>     Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>     Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>     Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>     Link: https://patchwork.freedesktop.org/patch/msgid/20240308204741.3631919-1-sean.anderson@linux.dev
>     (cherry picked from commit 61ba791c4a7a09a370c45b70a81b8c7d4cf6b2ae)
>     Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>     Signed-off-by: Sasha Levin <sashal@kernel.org>
> 
> diff --git a/drivers/gpu/drm/xlnx/zynqmp_dpsub.c b/drivers/gpu/drm/xlnx/zynqmp_dpsub.c
> index 88eb33acd5f0d..face8d6b2a6fb 100644
> --- a/drivers/gpu/drm/xlnx/zynqmp_dpsub.c
> +++ b/drivers/gpu/drm/xlnx/zynqmp_dpsub.c
> @@ -256,12 +256,12 @@ static int zynqmp_dpsub_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto err_dp;
>  
> +	drm_bridge_add(dpsub->bridge);
> +
>  	if (dpsub->dma_enabled) {
>  		ret = zynqmp_dpsub_drm_init(dpsub);
>  		if (ret)
>  			goto err_disp;
> -	} else {
> -		drm_bridge_add(dpsub->bridge);
>  	}
>  
>  	dev_info(&pdev->dev, "ZynqMP DisplayPort Subsystem driver probed");
> @@ -288,9 +288,8 @@ static void zynqmp_dpsub_remove(struct platform_device *pdev)
>  
>  	if (dpsub->drm)
>  		zynqmp_dpsub_drm_cleanup(dpsub);
> -	else
> -		drm_bridge_remove(dpsub->bridge);
>  
> +	drm_bridge_remove(dpsub->bridge);
>  	zynqmp_disp_remove(dpsub);
>  	zynqmp_dp_remove(dpsub);
>