On Thu, May 04, 2023 at 02:10:47AM +0300, Imre Deak wrote: > 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@xxxxxxxxxxxxxxx/ > > 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@xxxxxxxxxxxxxxx> > Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx> Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/Makefile | 1 + > drivers/gpu/drm/i915/display/intel_ddi.c | 17 ++----- > .../gpu/drm/i915/display/intel_modeset_lock.c | 50 +++++++++++++++++++ > .../gpu/drm/i915/display/intel_modeset_lock.h | 33 ++++++++++++ > 4 files changed, 87 insertions(+), 14 deletions(-) > create mode 100644 drivers/gpu/drm/i915/display/intel_modeset_lock.c > create mode 100644 drivers/gpu/drm/i915/display/intel_modeset_lock.h > > diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile > index 9af76e376ca91..ef6feb2aad2ad 100644 > --- a/drivers/gpu/drm/i915/Makefile > +++ b/drivers/gpu/drm/i915/Makefile > @@ -263,6 +263,7 @@ 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 \ > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c > index 55f36d9d509c6..eb391fff0f1be 100644 > --- a/drivers/gpu/drm/i915/display/intel_ddi.c > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c > @@ -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" > @@ -4400,26 +4401,14 @@ 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 > diff --git a/drivers/gpu/drm/i915/display/intel_modeset_lock.c b/drivers/gpu/drm/i915/display/intel_modeset_lock.c > new file mode 100644 > index 0000000000000..8fb6fd849a75d > --- /dev/null > +++ b/drivers/gpu/drm/i915/display/intel_modeset_lock.c > @@ -0,0 +1,50 @@ > +// 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); > +} > diff --git a/drivers/gpu/drm/i915/display/intel_modeset_lock.h b/drivers/gpu/drm/i915/display/intel_modeset_lock.h > new file mode 100644 > index 0000000000000..edb5099bcd99c > --- /dev/null > +++ b/drivers/gpu/drm/i915/display/intel_modeset_lock.h > @@ -0,0 +1,33 @@ > +/* 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__ */ > -- > 2.37.2 -- Ville Syrjälä Intel
