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Message-ID: <ee27c832-a1fd-bc93-9f1b-33f828195e83@amd.com>
Date: Wed, 7 Sep 2022 10:10:52 +0200
From: Christian König <christian.koenig@....com>
To: Thomas Zimmermann <tzimmermann@...e.de>,
oushixiong <oushixiong@...inos.cn>,
Dave Airlie <airlied@...hat.com>
Cc: David Airlie <airlied@...ux.ie>, linux-kernel@...r.kernel.org,
dri-devel@...ts.freedesktop.org,
Sumit Semwal <sumit.semwal@...aro.org>,
linaro-mm-sig@...ts.linaro.org, linux-media@...r.kernel.org
Subject: Re: [PATCH v3] drm/ast: add dmabuf/prime buffer sharing support
Hi Thomas,
I was wondering pretty much the same thing, but then thought that this
might be the first step to direct scanout from DMA-bufs.
If this isn't the case then I to see this rather critically since that
functionality belongs into userspace.
Regards,
Christian.
Am 07.09.22 um 09:50 schrieb Thomas Zimmermann:
> Hi,
>
> on a more general note, let me say that your patch doesn't seem to fit
> the ideas of how buffer sharing is supposed to work. Your patch does
> the BMC screen update 'behind the scenes.'
>
> Shouldn't userspace set up the DRM state for mirroring the output of
> the discrete card to the BMC?
>
> Best regards
> Thomas
>
> Am 01.09.22 um 14:44 schrieb oushixiong:
>>
>> This patch adds ast specific codes for DRM prime feature, this is to
>> allow for offloading of rending in one direction and outputs in other.
>>
>> This patch is designed to solve the problem that the AST is not
>> displayed
>> when the server plug in a discrete graphics card at the same time.
>> We call the dirty callback function to copy the rendering results of the
>> discrete graphics card to the ast side by dma-buf.
>>
>> v1->v2:
>> - Fix the comment.
>> v2->v3:
>> - we remove the gem_prime_import_sg_table callback and use the
>> gem_prime_import callback, because it just map and access the
>> buffer
>> with the CPU. and do not to pin the buffer.
>>
>> Signed-off-by: oushixiong <oushixiong@...inos.cn>
>> Acked-by: Christian König <christian.koenig@....com>
>> ---
>> drivers/gpu/drm/ast/ast_drv.c | 27 +++++++
>> drivers/gpu/drm/ast/ast_mode.c | 125 ++++++++++++++++++++++++++++++++-
>> 2 files changed, 151 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/ast/ast_drv.c
>> b/drivers/gpu/drm/ast/ast_drv.c
>> index 7465c4f0156a..fd3c4bad2eb4 100644
>> --- a/drivers/gpu/drm/ast/ast_drv.c
>> +++ b/drivers/gpu/drm/ast/ast_drv.c
>> @@ -28,6 +28,7 @@
>> #include <linux/module.h>
>> #include <linux/pci.h>
>> +#include <linux/dma-buf.h>
>> #include <drm/drm_aperture.h>
>> #include <drm/drm_atomic_helper.h>
>> @@ -50,6 +51,29 @@ module_param_named(modeset, ast_modeset, int, 0400);
>> DEFINE_DRM_GEM_FOPS(ast_fops);
>> +static struct drm_gem_object *ast_gem_prime_import(struct
>> drm_device *dev,
>> + struct dma_buf *dma_buf)
>> +{
>> + struct drm_gem_vram_object *gbo;
>> +
>> + gbo = drm_gem_vram_of_gem(dma_buf->priv);
>> + if (gbo->bo.base.dev == dev) {
>> + /*
>> + * Importing dmabuf exported from out own gem increases
>> + * refcount on gem itself instead of f_count of dmabuf.
>> + */
>> + drm_gem_object_get(&gbo->bo.base);
>> + return &gbo->bo.base;
>> + }
>> +
>> + gbo = drm_gem_vram_create(dev, dma_buf->size, 0);
>> + if (IS_ERR(gbo))
>> + return NULL;
>> +
>> + get_dma_buf(dma_buf);
>> + return &gbo->bo.base;
>> +}
>> +
>> static const struct drm_driver ast_driver = {
>> .driver_features = DRIVER_ATOMIC |
>> DRIVER_GEM |
>> @@ -63,6 +87,9 @@ static const struct drm_driver ast_driver = {
>> .minor = DRIVER_MINOR,
>> .patchlevel = DRIVER_PATCHLEVEL,
>> + .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
>> + .gem_prime_import = ast_gem_prime_import,
>> +
>> DRM_GEM_VRAM_DRIVER
>> };
>> diff --git a/drivers/gpu/drm/ast/ast_mode.c
>> b/drivers/gpu/drm/ast/ast_mode.c
>> index 45b56b39ad47..65a4342c5622 100644
>> --- a/drivers/gpu/drm/ast/ast_mode.c
>> +++ b/drivers/gpu/drm/ast/ast_mode.c
>> @@ -48,6 +48,8 @@
>> #include "ast_drv.h"
>> #include "ast_tables.h"
>> +MODULE_IMPORT_NS(DMA_BUF);
>> +
>> static inline void ast_load_palette_index(struct ast_private *ast,
>> u8 index, u8 red, u8 green,
>> u8 blue)
>> @@ -1535,8 +1537,129 @@ static const struct
>> drm_mode_config_helper_funcs ast_mode_config_helper_funcs =
>> .atomic_commit_tail = drm_atomic_helper_commit_tail_rpm,
>> };
>> +static int ast_handle_damage(struct drm_framebuffer *fb, int x,
>> int y,
>> + int width, int height)
>> +{
>> + struct drm_gem_vram_object *dst_bo = NULL;
>> + void *dst = NULL;
>> + int ret = 0, i;
>> + unsigned long offset = 0;
>> + bool unmap = false;
>> + unsigned int bytesPerPixel;
>> + struct iosys_map map;
>> + struct iosys_map dmabuf_map;
>> +
>> + bytesPerPixel = fb->format->cpp[0];
>> +
>> + if (!fb->obj[0]->dma_buf)
>> + return -EINVAL;
>> +
>> + if (!fb->obj[0]->dma_buf->vmap_ptr.vaddr) {
>> + ret = dma_buf_vmap(fb->obj[0]->dma_buf, &dmabuf_map);
>> + if (ret)
>> + return ret;
>> + } else
>> + dmabuf_map.vaddr = fb->obj[0]->dma_buf->vmap_ptr.vaddr;
>> +
>> + dst_bo = drm_gem_vram_of_gem(fb->obj[0]);
>> +
>> + ret = drm_gem_vram_pin(dst_bo, 0);
>> + if (ret) {
>> + DRM_ERROR("ast_bo_pin failed\n");
>> + return ret;
>> + }
>> +
>> + if (!dst_bo->map.vaddr) {
>> + ret = drm_gem_vram_vmap(dst_bo, &map);
>> + if (ret) {
>> + drm_gem_vram_unpin(dst_bo);
>> + DRM_ERROR("failed to vmap fbcon\n");
>> + return ret;
>> + }
>> + unmap = true;
>> + }
>> + dst = dst_bo->map.vaddr;
>> +
>> + for (i = y; i < y + height; i++) {
>> + offset = i * fb->pitches[0] + (x * bytesPerPixel);
>> + memcpy_toio(dst + offset, dmabuf_map.vaddr + offset,
>> + width * bytesPerPixel);
>> + }
>> +
>> + if (unmap)
>> + drm_gem_vram_vunmap(dst_bo, &map);
>> +
>> + drm_gem_vram_unpin(dst_bo);
>> +
>> + return 0;
>> +}
>> +
>> +
>> +static int ast_user_framebuffer_dirty(struct drm_framebuffer *fb,
>> + struct drm_file *file,
>> + unsigned int flags,
>> + unsigned int color,
>> + struct drm_clip_rect *clips,
>> + unsigned int num_clips)
>> +{
>> + int i, ret = 0;
>> +
>> + drm_modeset_lock_all(fb->dev);
>> + if (fb->obj[0]->dma_buf) {
>> + ret = dma_buf_begin_cpu_access(fb->obj[0]->dma_buf,
>> + DMA_FROM_DEVICE);
>> + if (ret)
>> + goto unlock;
>> + }
>> +
>> + for (i = 0; i < num_clips; i++) {
>> + ret = ast_handle_damage(fb, clips[i].x1, clips[i].y1,
>> + clips[i].x2 - clips[i].x1, clips[i].y2 - clips[i].y1);
>> + if (ret)
>> + break;
>> + }
>> +
>> + if (fb->obj[0]->dma_buf) {
>> + dma_buf_end_cpu_access(fb->obj[0]->dma_buf,
>> + DMA_FROM_DEVICE);
>> + }
>> +
>> +unlock:
>> + drm_modeset_unlock_all(fb->dev);
>> +
>> + return ret;
>> +}
>> +
>> +static void ast_user_framebuffer_destroy(struct drm_framebuffer *fb)
>> +{
>> + struct iosys_map dmabuf_map;
>> +
>> + if (fb->obj[0]->dma_buf) {
>> + dmabuf_map.is_iomem = fb->obj[0]->dma_buf->vmap_ptr.is_iomem;
>> + dmabuf_map.vaddr = fb->obj[0]->dma_buf->vmap_ptr.vaddr;
>> + if (dmabuf_map.vaddr)
>> + dma_buf_vunmap(fb->obj[0]->dma_buf, &dmabuf_map);
>> + }
>> +
>> + drm_gem_fb_destroy(fb);
>> +}
>> +
>> +static const struct drm_framebuffer_funcs ast_gem_fb_funcs_dirtyfb = {
>> + .destroy = ast_user_framebuffer_destroy,
>> + .create_handle = drm_gem_fb_create_handle,
>> + .dirty = ast_user_framebuffer_dirty,
>> +};
>> +
>> +static struct drm_framebuffer *
>> +ast_gem_fb_create_with_dirty(struct drm_device *dev, struct drm_file
>> *file,
>> + const struct drm_mode_fb_cmd2 *mode_cmd)
>> +{
>> + return drm_gem_fb_create_with_funcs(dev, file, mode_cmd,
>> + &ast_gem_fb_funcs_dirtyfb);
>> +}
>> +
>> static const struct drm_mode_config_funcs ast_mode_config_funcs = {
>> - .fb_create = drm_gem_fb_create,
>> + .fb_create = ast_gem_fb_create_with_dirty,
>> .mode_valid = drm_vram_helper_mode_valid,
>> .atomic_check = drm_atomic_helper_check,
>> .atomic_commit = drm_atomic_helper_commit,
>>
>>
>> Content-type: Text/plain
>>
>> No virus found
>> Checked by Hillstone Network AntiVirus
>
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