Re: [PATCH 1/4] drm: allow drm_atomic_print_state() to accept any drm_printer

abhinavk
2020-10-30T01:12:40Z

Hi Daniel

On 2020-10-22 03:38, Daniel Vetter wrote:
> On Wed, Oct 21, 2020 at 10:01:45PM -0700, Abhinav Kumar wrote:
>> Currently drm_atomic_print_state() internally allocates and uses a
>> drm_info printer. Allow it to accept any drm_printer type so that
>> the API can be leveraged even for taking drm snapshot.
>>
>> Signed-off-by: Abhinav Kumar <abhinavk@codeaurora.org>
>> ---
>> drivers/gpu/drm/drm_atomic.c | 17 ++++++++++++-----
>> drivers/gpu/drm/drm_atomic_uapi.c | 4 +++-
>> drivers/gpu/drm/drm_crtc_internal.h | 4 +++-
>> 3 files changed, 18 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_atomic.c
>> b/drivers/gpu/drm/drm_atomic.c
>> index 58527f151984..e7079a5f439c 100644
>> --- a/drivers/gpu/drm/drm_atomic.c
>> +++ b/drivers/gpu/drm/drm_atomic.c
>> @@ -1,6 +1,7 @@
>> /*
>> * Copyright (C) 2014 Red Hat
>> * Copyright (C) 2014 Intel Corp.
>> + * Copyright (c) 2020, The Linux Foundation. All rights reserved.
>> *
>> * Permission is hereby granted, free of charge, to any person
>> obtaining a
>> * copy of this software and associated documentation files (the
>> "Software"),
>> @@ -1543,9 +1544,9 @@ int __drm_atomic_helper_set_config(struct
>> drm_mode_set *set,
>> }
>> EXPORT_SYMBOL(__drm_atomic_helper_set_config);
>>
>> -void drm_atomic_print_state(const struct drm_atomic_state *state)
>> +void drm_atomic_print_state(const struct drm_atomic_state *state,
>> + struct drm_printer *p)
>
> Please add a nice kerneldoc for this newly exported function.
> Specifically
> this kerneldoc needs to include a warning that state updates after call
> drm_atomic_state_helper_commit_hw_done() is unsafe to print using this
> function, because it looks at the new state objects. Only the old state
> structures will stay like this.
>
> So maybe rename the function to say print_new_state() to make this
> completely clear. That way we can eventually add a print_old_state()
> when
> needed.
>
> Otherwise I think this makes sense, and nicely avoids the locking issue
> of
> looking at ->state pointers without the right locking.
> -Daniel
>

Thanks for the review, I have addressed these comments and posted a V2.
-Abhinav

>> {
>> - struct drm_printer p = drm_info_printer(state->dev->dev);
>> struct drm_plane *plane;
>> struct drm_plane_state *plane_state;
>> struct drm_crtc *crtc;
>> @@ -1554,17 +1555,23 @@ void drm_atomic_print_state(const struct
>> drm_atomic_state *state)
>> struct drm_connector_state *connector_state;
>> int i;
>>
>> + if (!p) {
>> + DRM_ERROR("invalid drm printer\n");
>> + return;
>> + }
>> +
>> DRM_DEBUG_ATOMIC("checking %p\n", state);
>>
>> for_each_new_plane_in_state(state, plane, plane_state, i)
>> - drm_atomic_plane_print_state(&p, plane_state);
>> + drm_atomic_plane_print_state(p, plane_state);
>>
>> for_each_new_crtc_in_state(state, crtc, crtc_state, i)
>> - drm_atomic_crtc_print_state(&p, crtc_state);
>> + drm_atomic_crtc_print_state(p, crtc_state);
>>
>> for_each_new_connector_in_state(state, connector, connector_state,
>> i)
>> - drm_atomic_connector_print_state(&p, connector_state);
>> + drm_atomic_connector_print_state(p, connector_state);
>> }
>> +EXPORT_SYMBOL(drm_atomic_print_state);
>>
>> static void __drm_state_dump(struct drm_device *dev, struct
>> drm_printer *p,
>> bool take_locks)
>> diff --git a/drivers/gpu/drm/drm_atomic_uapi.c
>> b/drivers/gpu/drm/drm_atomic_uapi.c
>> index 25c269bc4681..d9ae86c92608 100644
>> --- a/drivers/gpu/drm/drm_atomic_uapi.c
>> +++ b/drivers/gpu/drm/drm_atomic_uapi.c
>> @@ -2,6 +2,7 @@
>> * Copyright (C) 2014 Red Hat
>> * Copyright (C) 2014 Intel Corp.
>> * Copyright (C) 2018 Intel Corp.
>> + * Copyright (c) 2020, The Linux Foundation. All rights reserved.
>> *
>> * Permission is hereby granted, free of charge, to any person
>> obtaining a
>> * copy of this software and associated documentation files (the
>> "Software"),
>> @@ -1294,6 +1295,7 @@ int drm_mode_atomic_ioctl(struct drm_device
>> *dev,
>> struct drm_out_fence_state *fence_state;
>> int ret = 0;
>> unsigned int i, j, num_fences;
>> + struct drm_printer p = drm_info_printer(dev->dev);
>>
>> /* disallow for drivers not supporting atomic: */
>> if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
>> @@ -1413,7 +1415,7 @@ int drm_mode_atomic_ioctl(struct drm_device
>> *dev,
>> ret = drm_atomic_nonblocking_commit(state);
>> } else {
>> if (drm_debug_enabled(DRM_UT_STATE))
>> - drm_atomic_print_state(state);
>> + drm_atomic_print_state(state, &p);
>>
>> ret = drm_atomic_commit(state);
>> }
>> diff --git a/drivers/gpu/drm/drm_crtc_internal.h
>> b/drivers/gpu/drm/drm_crtc_internal.h
>> index da96b2f64d7e..d34215366936 100644
>> --- a/drivers/gpu/drm/drm_crtc_internal.h
>> +++ b/drivers/gpu/drm/drm_crtc_internal.h
>> @@ -5,6 +5,7 @@
>> * Jesse Barnes <jesse.barnes@intel.com>
>> * Copyright © 2014 Intel Corporation
>> * Daniel Vetter <daniel.vetter@ffwll.ch>
>> + * Copyright (c) 2020, The Linux Foundation. All rights reserved.
>> *
>> * Permission is hereby granted, free of charge, to any person
>> obtaining a
>> * copy of this software and associated documentation files (the
>> "Software"),
>> @@ -233,7 +234,8 @@ int __drm_atomic_helper_disable_plane(struct
>> drm_plane *plane,
>> int __drm_atomic_helper_set_config(struct drm_mode_set *set,
>> struct drm_atomic_state *state);
>>
>> -void drm_atomic_print_state(const struct drm_atomic_state *state);
>> +void drm_atomic_print_state(const struct drm_atomic_state *state,
>> + struct drm_printer *p);
>>
>> /* drm_atomic_uapi.c */
>> int drm_atomic_connector_commit_dpms(struct drm_atomic_state *state,
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
>> Forum,
>> a Linux Foundation Collaborative Project
>>
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