Commit 60ded7cc authored by Imre Deak's avatar Imre Deak
Browse files

drm/i915: Factor out a helper for handling atomic modeset locks/state 

This patch simplifying the handling of modeset locks and atomic state
for an atomic commit is based on

https://lore.kernel.org/all/20210715184954.7794-2-ville.syrjala@linux.intel.com/



adding the helper to i915. I find this approach preferrable than
open-coding the corresponding steps (fixed for me an atomic
state reset during a DEADLK retry, which I missed in the open-coded
version) and also better than the existing
DRM_MODESET_LOCK_ALL_BEGIN/END macros for the reasons described in the
above original patchset.

This change takes the helper into use only for atomic commits during DDI
hotplug handling, as a preparation for a follow-up patch adding a
similar commit started from the same spot. Other places doing a
driver-internal atomic commit is to be converted by a follow-up
patchset.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarImre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230510103131.1618266-13-imre.deak@intel.com
parent 7e4460c3

drivers/gpu/drm/i915/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -265,6 +265,7 @@ i915-y += \ 
	display/intel_hti.o \

	display/intel_load_detect.o \

	display/intel_lpe_audio.o \

	display/intel_modeset_lock.o \

	display/intel_modeset_verify.o \

	display/intel_modeset_setup.o \

	display/intel_overlay.o \

drivers/gpu/drm/i915/display/intel_ddi.c

+3 −14
Original line number Diff line number Diff line
@@ -63,6 +63,7 @@ 
#include "intel_hti.h"

#include "intel_lspcon.h"

#include "intel_mg_phy_regs.h"

#include "intel_modeset_lock.h"

#include "intel_pps.h"

#include "intel_psr.h"

#include "intel_quirks.h"
@@ -4401,26 +4402,14 @@ intel_ddi_hotplug(struct intel_encoder *encoder, 


	state = intel_encoder_hotplug(encoder, connector);



	drm_modeset_acquire_init(&ctx, 0);



	for (;;) {

	intel_modeset_lock_ctx_retry(&ctx, NULL, 0, ret) {

		if (connector->base.connector_type == DRM_MODE_CONNECTOR_HDMIA)

			ret = intel_hdmi_reset_link(encoder, &ctx);

		else

			ret = intel_dp_retrain_link(encoder, &ctx);



		if (ret == -EDEADLK) {

			drm_modeset_backoff(&ctx);

			continue;

		}



		break;

	}



	drm_modeset_drop_locks(&ctx);

	drm_modeset_acquire_fini(&ctx);

	drm_WARN(encoder->base.dev, ret,

		 "Acquiring modeset locks failed with %i\n", ret);

	drm_WARN_ON(encoder->base.dev, ret);



	/*

	 * Unpowered type-c dongles can take some time to boot and be

drivers/gpu/drm/i915/display/intel_modeset_lock.c

0 → 100644
+50 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: MIT

/*

 * Copyright © 2023 Intel Corporation

 */



#include <drm/drm_modeset_lock.h>



#include "intel_display_types.h"

#include "intel_modeset_lock.h"



void _intel_modeset_lock_begin(struct drm_modeset_acquire_ctx *ctx,

			       struct intel_atomic_state *state,

			       unsigned int flags, int *ret)

{

	drm_modeset_acquire_init(ctx, flags);



	if (state)

		state->base.acquire_ctx = ctx;



	*ret = -EDEADLK;

}



bool _intel_modeset_lock_loop(int *ret)

{

	if (*ret == -EDEADLK) {

		*ret = 0;

		return true;

	}



	return false;

}



void _intel_modeset_lock_end(struct drm_modeset_acquire_ctx *ctx,

			     struct intel_atomic_state *state,

			     int *ret)

{

	if (*ret == -EDEADLK) {

		if (state)

			drm_atomic_state_clear(&state->base);



		*ret = drm_modeset_backoff(ctx);

		if (*ret == 0) {

			*ret = -EDEADLK;

			return;

		}

	}



	drm_modeset_drop_locks(ctx);

	drm_modeset_acquire_fini(ctx);

}

drivers/gpu/drm/i915/display/intel_modeset_lock.h

0 → 100644
+33 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: MIT */

/*

 * Copyright © 2023 Intel Corporation

 */



#ifndef __INTEL_MODESET_LOCK_H__

#define __INTEL_MODESET_LOCK_H__



#include <linux/types.h>



struct drm_modeset_acquire_ctx;

struct intel_atomic_state;



void _intel_modeset_lock_begin(struct drm_modeset_acquire_ctx *ctx,

			       struct intel_atomic_state *state,

			       unsigned int flags,

			       int *ret);

bool _intel_modeset_lock_loop(int *ret);

void _intel_modeset_lock_end(struct drm_modeset_acquire_ctx *ctx,

			     struct intel_atomic_state *state,

			     int *ret);



/*

 * Note that one must always use "continue" rather than

 * "break" or "return" to handle errors within the

 * intel_modeset_lock_ctx_retry() block.

 */

#define intel_modeset_lock_ctx_retry(ctx, state, flags, ret) \

	for (_intel_modeset_lock_begin((ctx), (state), (flags), &(ret)); \

	     _intel_modeset_lock_loop(&(ret)); \

	     _intel_modeset_lock_end((ctx), (state), &(ret)))



#endif /* __INTEL_MODESET_LOCK_H__ */