Hi Junghak, I've accepted this v6 series and made a pull request for Mauro. I am still not happy about the queue_setup patch, but that can be changed later. Regards, Hans On 10/06/2015 11:37 AM, Junghak Sung wrote: > Hello everybody, > > This is the 6th round for refactoring Videobuf2(a.k.a VB2). > The purpose of this patch series is to separate existing VB2 framework > into core part and V4L2 specific part. So that not only V4L2 but also other > frameworks can use them to manage buffer and utilize queue. > > Why do we try to make the VB2 framework to be common? > > As you may know, current DVB framework uses ringbuffer mechanism to demux > MPEG-2 TS data and pass it to userspace. However, this mechanism requires > extra memory copy because DVB framework provides only read() system call for > application - read() system call copies the kernel data to user-space buffer. > So if we can use VB2 framework which supports streaming I/O and buffer > sharing mechanism, then we could enhance existing DVB framework by removing > the extra memory copy - with VB2 framework, application can access the kernel > data directly through mmap system call. > > We have a plan for this work as follows: > 1. Separate existing VB2 framework into three parts - VB2 core, VB2 v4l2. > Of course, this change will not affect other v4l2-based > device drivers. This patch series corresponds to this step. > > 2. Add and implement new APIs for DVB streaming I/O. > We can remove unnecessary memory copy between kernel-space and user-space > by using these new APIs. However, we leaves legacy interfaces as-is > for backward compatibility. > > This patch series is the first step for it. > The previous version of this patch series can be found at belows. > > [1] RFC PATCH v1 - http://www.spinics.net/lists/linux-media/msg90688.html > [2] RFC PATCH v2 - http://www.spinics.net/lists/linux-media/msg92130.html > [3] RFC PATCH v3 - http://www.spinics.net/lists/linux-media/msg92953.html > [4] RFC PATCH v4 - http://www.spinics.net/lists/linux-media/msg93421.html > [5] RFC PATCH v5 - http://www.spinics.net/lists/linux-media/msg93810.html > > Changes since v5 > 1. v5 is merged partially to media_tree > 4 of 8 patches - restructuring vb2_buffer for common use - are merged to > media_tree. So, v6 is rebased on later version than that. > > 2. vb2_format is reverted to void * > vb2_format - which is newly defined for queue_setup() in v5 to deliver > the format information from user-space to device driver - is reverted to > void pointer. This change requires more discussion about the way to do > the format validation and decide the image size. > So, in this version, I would like to revert it to original version. > > 3. The change related with v4l2_buf_ops is moved > The change related with v4l2_buf_ops seems to be a sort of functional change. > So, it was moved to patch 3/4 - which includes the most of functional changes. > > > Changes since v4 > 1. Rebase on 4.3-rc1 > Kernel 4.3-rc1 was released. So, this patch set is made based on > that version. > > 2. Modify queue_setup() argument > In previous patch set, struct v4l2_format, which is a parameter of > queue_setup(), is abstracted by using void pointer. But, it is better way to > pass the parameter with presise meaning than abstracting it. > So, replace void * with struct vb2_format which is newly defined to contain > the format information for common use. > > 3. Add a code to check if VB2_MAX_* match with VIDEO_MAX_* > Add a check code to videobuf2-v4l2.c where the compiler compares VIDEO_MAX_FRAME > and VB2_MAX_FRAME (and ditto for MAX_PLANES) and throws an #error if they > do not match. > > 4. Change the commit order > For easier review, the patch that just move things around without doing any > functional change is moved to the last. > > All ideas above are from Hans and it seems to be better and right way. > > > Changes since v3 > > 1. Resolve build errors > In previous patch set, the build errors prevented reviewers from applying > the patch. So, in this patch, I tryed to fix the build errors but I hadn't > the build test on all architectures except for x86 and ARM. > > 2. Modify descriptions for DocBook > Descriptions not complying with the DocBook rule are modified, > which was pointed out by Mauro. > > 3. Initialize reserved fields explicitly > The reserved fields of v4l2_buffer are initialized by 0 explicitly > when the vb2_buffer information is returned to userspace, > which was pointed out by Hans. > > 4. Remove unnecessary type-cast > According to Mauro's advice, the unnecessary type-cast are removed > because it's better for the compiler - rather than human - to check those > things. > > 5. Sperate the patch - not easy to review - into two patches > In previous patch set, patch 5 was too difficult to review. So accoring to > Hans' opinion, it separated the patch without any functional changes. > > > Changes since v2 > > 1. Remove v4l2 stuffs completely from vb2_buffer > The v4l2 stuffs - v4l2_buf and v4l2_planes - are removed completely from > struct vb2_buffer. New member variables - index, type, memory - are added > to struct vb2_buffer, all of which can be used commonly. And bytesused, > length, offset, userptr, fd, data_offset are added to struct vb2_plane > for the same reason. So, we can manage video buffer by only using > struct vb2_buffer. > And, v4l2 stuffs - flags, field, timestamp, timecode, sequence - are defined > as member variables of struct vb2_v4l2_buffer. > > 2. Create new header file for VB2 internal use > videobuf2-internal.h is created, which is referred by videobuf2-core > and videobuf2-v4l2. The header file contains dprintk() for debug, > macro functions to invoke various callbacks, and vb2_core_* function prototypes > referred by inside of videobuf2. > > 3. Remove buffer-specific callbacks as much as possible > There were many callback functions to handle video buffer information > in previous patch series. In this patch series, I try to remove these callbacks > as much as possible without breaking the existing function flow. > As a result, only four callbacks are remained - fill_user_buffer(), > fill_vb2_buffer(), fill_vb2_timestamp() and is_last(). > > All ideas above are from Hans and it seems to be better and right way. > > > Changes since v1 > > 1. Divide patch set into more pieces > v1 was not reviewed normally because the 2/3 patch is failed to send to mailing > list with size problem - over 300kb. So I have divided the patch set into five > pieces and refined them neatly, which was pointed by Hans. > > 2. Add shell scripts for renaming patch > In case of renaming patch, shell scripts are included inside the body of the > patches by Mauro's advice. 1/5 and 5/5 patches include these scripts, which can > be used by reviewers or maintainers to regenerate big patch file if something > goes wrong during patch apply. > > 3. Remove dependency on v4l2 from videobuf2 > In previous patch set, videobuf2-core uses v4l2-specific stuff as it is. > e.g. enum v4l2_buf_type and enum v4l2_memory. That prevented other frameworks > from using videobuf2 independently and made them forced to include > v4l2-specific stuff. > In this version, these dependent stuffs are replaced with VB2 own stuffs. > e.g. enum vb2_buf_type and enum vb2_memory. So, v4l2-specific header file isn't > required to use videobuf2 in other modules. Please, note that videobuf2 stuffs > will be translated to v4l2-specific stuffs in videobuf2-v4l2.c file for > backward compatibility. > > 4. Unify duplicated definitions > VB2_DEBUG() is newly defined in videobuf2-core header file in order to unify > duplicated macro functions that invoke callback functions implemented in vb2 > backends - i.e., videobuf2-vmalloc and videobuf2-dma-sg - and queue relevant > callbacks of device drivers. > In previous patch set, these macro functions were defined > in both videobuf2-core.c and videobuf2-v4l2.c. > > > This patch series is based on media_tree.git [6]. I have applied this patches > to my own git [7] for review, and tested this patch series on ubuntu > PC(Intel i7-3770) for x86 system and odroid-xu3(exynos5422) for ARM. > > [6] media_tree.git - http://git.linuxtv.org/cgit.cgi/media_tree.git/ > [7] jsung/dvb-vb2.git - http://git.linuxtv.org/cgit.cgi/jsung/dvb-vb2.git/ > (branch: vb2-refactoring) > > Any suggestions and comments are welcome. > > Regards, > Junghak -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
