[libcamera-devel] [PATCH v2 4/4] android: mm: generic: Use GraphicBufferAllocator instead of gralloc.h

Mattijs Korpershoek mkorpershoek at baylibre.com
Sat Sep 23 12:31:29 CEST 2023


Hi Jacopo,

Thank you for your review.

On ven., sept. 22, 2023 at 11:27, Jacopo Mondi <jacopo.mondi at ideasonboard.com> wrote:

> HI Mattijs
>
>  nice work!
>
> On Tue, Sep 12, 2023 at 04:15:23PM +0200, Mattijs Korpershoek via libcamera-devel wrote:
>> gralloc.h is a very old API that has been deprecated at least since
>> Android P (9).
>>
>> Switch over to a higher level abstraction of gralloc from libui, which
>> is compatible with Android 11 and up.
>> Libui
:
>> * is provided in the VNDK (so it's available to vendors).
>> * is also used in the camera vts test named VtsAidlHalCameraProvider_TargetTest.
>>
>> Drop the libhardware stub since we no longer need it.
>>
>> Notes:
>> * GraphicsBufferAllocator being a Singleton, buffer lifecycle
>>   management is easier.
>> * The imported headers from Android generate the -Wextra-semi warning.
>>   To avoid patching the files, a pragma has been added before inclusion.
>>
>> Signed-off-by: Mattijs Korpershoek <mkorpershoek at baylibre.com>
>> ---
>>  src/android/mm/generic_frame_buffer_allocator.cpp | 61 ++++++++---------------
>>  src/android/mm/libhardware_stub.c                 | 17 -------
>>  src/android/mm/meson.build                        |  8 ++-
>>  3 files changed, 23 insertions(+), 63 deletions(-)
>>
>> diff --git a/src/android/mm/generic_frame_buffer_allocator.cpp b/src/android/mm/generic_frame_buffer_allocator.cpp
>> index 7ecef2c669df..468579068c32 100644
>> --- a/src/android/mm/generic_frame_buffer_allocator.cpp
>> +++ b/src/android/mm/generic_frame_buffer_allocator.cpp
>> @@ -16,8 +16,11 @@
>>  #include "libcamera/internal/framebuffer.h"
>>
>>  #include <hardware/camera3.h>
>> -#include <hardware/gralloc.h>
>
> our version of include/android/system/core/include/system/camera.h
> still includes gralloc.h. We should update all headers most probably

That's also the case for the one in aosp main:

https://cs.android.com/android/platform/superproject/main/+/main:system/core/libsystem/include/system/camera.h?q=camera.h%20&ss=android%2Fplatform%2Fsuperproject%2Fmain

How about, instead, we get rid of the unused headers (which were copied
from AOSP) in the libcamera include/android tree instead?

If that seems fine, I will do some cleaning up and get rid of the
"no-longer needed" headers in a new patch for v2.


>
>> -#include <hardware/hardware.h>
>> +#pragma GCC diagnostic push
>> +#pragma GCC diagnostic ignored "-Wextra-semi"
>> +#include <ui/GraphicBufferAllocator.h>
>> +#pragma GCC diagnostic pop
>> +#include <utils/Errors.h>
>>
>>  #include "../camera_device.h"
>>  #include "../frame_buffer_allocator.h"
>> @@ -33,35 +36,28 @@ class GenericFrameBufferData : public FrameBuffer::Private
>>  	LIBCAMERA_DECLARE_PUBLIC(FrameBuffer)
>>
>>  public:
>> -	GenericFrameBufferData(struct alloc_device_t *allocDevice,
>> +	GenericFrameBufferData(android::GraphicBufferAllocator &allocDevice,
>
> You could
>
>         GenericFrameBufferData(buffer_handle_t handle,
>                                const std::vector<FrameBuffer::Plane> &planes)
>                 : FrameBuffer::Private(planes),
>                   allocDevice_(android::GraphicBufferAllocator::get()),
>                   handle_(handle)
>
> Instead of passing it to the constructor of ::Private.
> It does't make much different though, up to you!

I will give it some thought and either change it for v2 or put a note in
the cover to explain why I kept it the same.

>
>>  			       buffer_handle_t handle,
>>  			       const std::vector<FrameBuffer::Plane> &planes)
>>  		: FrameBuffer::Private(planes), allocDevice_(allocDevice),
>>  		  handle_(handle)
>>  	{
>> -		ASSERT(allocDevice_);
>>  		ASSERT(handle_);
>>  	}
>>
>>  	~GenericFrameBufferData() override
>>  	{
>>  		/*
>> -		 * allocDevice_ is used to destroy handle_. allocDevice_ is
>> -		 * owned by PlatformFrameBufferAllocator::Private.
>> -		 * GenericFrameBufferData must be destroyed before it is
>> -		 * destroyed.
>> -		 *
>> -		 * \todo Consider managing alloc_device_t with std::shared_ptr
>> -		 * if this is difficult to maintain.
>> -		 *
>
> nice!
>
>>  		 * \todo Thread safety against alloc_device_t is not documented.
>>  		 * Is it no problem to call alloc/free in parallel?
>>  		 */
>> -		allocDevice_->free(allocDevice_, handle_);
>> +		android::status_t status = allocDevice_.free(handle_);
>
> Or you could even get the singleton instance here!

You mean dropping the member and just getting the singleton instance with
android::GraphicBufferAllocator::get() ?

That might be even simpler and avoid adding an additional member indeed.

>
>> +		if (status != android::NO_ERROR)
>> +			LOG(HAL, Error) << "Error freeing framebuffer: " << status;
>>  	}
>>
>>  private:
>> -	struct alloc_device_t *allocDevice_;
>> +	android::GraphicBufferAllocator &allocDevice_;
>
> Usually reference class members are worrying to me, but this really
> just points to a system-wide component accessed via a singleton if i'm
> not mistaken, so this should be fine!

Yes, that is correct. I will study to remove the member for v2.

>
>
>>  	const buffer_handle_t handle_;
>>  };
>>  } /* namespace */
>> @@ -73,50 +69,33 @@ class PlatformFrameBufferAllocator::Private : public Extensible::Private
>>  public:
>>  	Private(CameraDevice *const cameraDevice)
>>  		: cameraDevice_(cameraDevice),
>> -		  hardwareModule_(nullptr),
>> -		  allocDevice_(nullptr)
>> +		  allocDevice_(android::GraphicBufferAllocator::get())
>>  	{
>> -		hw_get_module(GRALLOC_HARDWARE_MODULE_ID, &hardwareModule_);
>> -		ASSERT(hardwareModule_);
>>  	}
>>
>> -	~Private() override;
>> +	~Private() = default;
>>
>>  	std::unique_ptr<HALFrameBuffer>
>>  	allocate(int halPixelFormat, const libcamera::Size &size, uint32_t usage);
>>
>>  private:
>>  	const CameraDevice *const cameraDevice_;
>> -	const struct hw_module_t *hardwareModule_;
>> -	struct alloc_device_t *allocDevice_;
>> +	android::GraphicBufferAllocator &allocDevice_;
>>  };
>>
>> -PlatformFrameBufferAllocator::Private::~Private()
>> -{
>> -	if (allocDevice_)
>> -		gralloc_close(allocDevice_);
>> -	dlclose(hardwareModule_->dso);
>> -}
>> -
>>  std::unique_ptr<HALFrameBuffer>
>>  PlatformFrameBufferAllocator::Private::allocate(int halPixelFormat,
>>  						const libcamera::Size &size,
>>  						uint32_t usage)
>>  {
>> -	if (!allocDevice_) {
>> -		int ret = gralloc_open(hardwareModule_, &allocDevice_);
>> -		if (ret) {
>> -			LOG(HAL, Fatal) << "gralloc_open() failed: " << ret;
>> -			return nullptr;
>> -		}
>> -	}
>> -
>> -	int stride = 0;
>> +	uint32_t stride = 0;
>>  	buffer_handle_t handle = nullptr;
>> -	int ret = allocDevice_->alloc(allocDevice_, size.width, size.height,
>> -				      halPixelFormat, usage, &handle, &stride);
>> -	if (ret) {
>> -		LOG(HAL, Error) << "failed buffer allocation: " << ret;
>> +
>> +	android::status_t status = allocDevice_.allocate(size.width, size.height, halPixelFormat,
>> +							 1 /*layerCount*/, usage, &handle, &stride,
>> +							 "libcameraHAL");
>> +	if (status != android::NO_ERROR) {
>> +		LOG(HAL, Error) << "failed buffer allocation: " << status;
>>  		return nullptr;
>>  	}
>>  	if (!handle) {
>> diff --git a/src/android/mm/libhardware_stub.c b/src/android/mm/libhardware_stub.c
>> deleted file mode 100644
>> index 00f15cd90cac..000000000000
>> --- a/src/android/mm/libhardware_stub.c
>> +++ /dev/null
>> @@ -1,17 +0,0 @@
>> -/* SPDX-License-Identifier: Apache-2.0 */
>> -/*
>> - * Copyright (C) 2023, Ideas on Board
>> - *
>> - * libhardware_stub.c - Android libhardware stub for test compilation
>> - */
>> -
>> -#include <errno.h>
>> -
>> -#include <hardware/hardware.h>
>> -
>> -int hw_get_module(const char *id __attribute__((__unused__)),
>> -		  const struct hw_module_t **module)
>> -{
>> -	*module = NULL;
>> -	return -ENOTSUP;
>> -}
>> diff --git a/src/android/mm/meson.build b/src/android/mm/meson.build
>> index e9ceb3afba67..203b8c3e5804 100644
>> --- a/src/android/mm/meson.build
>> +++ b/src/android/mm/meson.build
>> @@ -4,13 +4,11 @@ platform = get_option('android_platform')
>>  if platform == 'generic'
>>      android_hal_sources += files(['generic_camera_buffer.cpp',
>>                                    'generic_frame_buffer_allocator.cpp'])
>> -    android_deps += [libdl]
>
> libdl was used for ?

for dlclose() call done in PlatformFrameBufferAllocator::Private::~Private().

For some background of why this was needed, refer to:
* 1450e09a0839 ("android: mm: generic: use GRALLOC_HARDWARE_MODULE_ID")
* https://patchwork.libcamera.org/patch/18309/#26496


>
>>
>> -    libhardware = dependency('libhardware', required : false)
>> -    if libhardware.found()
>> -        android_deps += [libhardware]
>> +    libui = dependency('libui', required : false)
>> +    if libui.found()
>> +        android_deps += [libui]
>>      else
>> -        android_hal_sources += files(['libhardware_stub.c'])
>>          android_hal_sources += files(['graphic_buffer_allocator_stub.cpp'])
>>      endif
>>  elif platform == 'cros'
>
> All nits
> Reviewed-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
>
> Thanks
>   j
>
>>
>> --
>> 2.41.0
>>


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