Re: [PATCH v2 5/5] drm/ingenic: Add option to alloc cached GEM buffers

[Paul Cercueil <paul@xxxxxxxxxxxxxxx>]

Hi Hillf,

Le lun. 8 mars 2021 à 11:47, Hillf Danton <hdanton@xxxxxxxx> a écrit :
> On Sun,  7 Mar 2021 20:28:35 +0000  Paul Cercueil wrote:
> >  With the module parameter ingenic-drm.cached_gem_buffers, it is 
> > possible
> >  to specify that we want GEM buffers backed by non-coherent memory.
> >
> >  This dramatically speeds up software rendering on Ingenic SoCs, 
> > even for
> >  tasks where write-combine memory should in theory be faster (e.g. 
> > simple
> >  blits).
>
> Wondering if it is due to the tricks at [1].
>
> If so, is dma_alloc_noncoherent() necessary in this patchset?

You confuse non-contiguous with non-coherent, which are two different 
things.

Cheers,
-Paul

> Christoph can you give us a concise lesson on noncoherency covering 
> at least
> noncoherent device, noncoherent memory(used in this work), no coherent
> caching(in [1]), their links to speedup, and the thumb rule to handle
> noncoherency in workdays. It feels toe curling every time I see 
> noncoherence
> going downtown with speedup hand in hand.
>
> [1] Subject: [PATCH 6/6] media: uvcvideo: Use dma_alloc_noncontiguos 
> API
> https://lore.kernel.org/lkml/20210301085236.947011-7-hch@xxxxxx/#t
>
> >  Leave it disabled by default, since it is specific to one use-case
> >  (software rendering).
> >
> >  v2: Rework code to work with new DRM APIs regarding plane states
> >
> >  Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> >  ---
> >   drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 49 
> > ++++++++++++++++++++++-
> >   drivers/gpu/drm/ingenic/ingenic-drm.h     |  4 ++
> >   drivers/gpu/drm/ingenic/ingenic-ipu.c     | 14 ++++++-
> >   3 files changed, 63 insertions(+), 4 deletions(-)
> >
> >  diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c 
> > b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> >  index d60e1eefc9d1..ba1ac0fcda74 100644
> >  --- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> >  +++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> >  @@ -9,6 +9,7 @@
> >   #include <linux/component.h>
> >   #include <linux/clk.h>
> >   #include <linux/dma-mapping.h>
> >  +#include <linux/io.h>
> >   #include <linux/module.h>
> >   #include <linux/mutex.h>
> >   #include <linux/of_device.h>
> >  @@ -23,6 +24,7 @@
> >   #include <drm/drm_color_mgmt.h>
> >   #include <drm/drm_crtc.h>
> >   #include <drm/drm_crtc_helper.h>
> >  +#include <drm/drm_damage_helper.h>
> >   #include <drm/drm_drv.h>
> >   #include <drm/drm_gem_cma_helper.h>
> >   #include <drm/drm_fb_cma_helper.h>
> >  @@ -99,6 +101,11 @@ struct ingenic_drm {
> >   	struct notifier_block clock_nb;
> >   };
> >
> >  +static bool ingenic_drm_cached_gem_buf;
> >  +module_param_named(cached_gem_buffers, ingenic_drm_cached_gem_buf, 
> > bool, 0400);
> >  +MODULE_PARM_DESC(cached_gem_buffers,
> >  +		 "Enable fully cached GEM buffers [default=false]");
> >  +
> >   static bool ingenic_drm_writeable_reg(struct device *dev, unsigned 
> > int reg)
> >   {
> >   	switch (reg) {
> >  @@ -410,6 +417,8 @@ static int 
> > ingenic_drm_plane_atomic_check(struct drm_plane *plane,
> >   	     old_plane_state->fb->format->format != 
> > new_plane_state->fb->format->format))
> >   		crtc_state->mode_changed = true;
> >
> >  +	drm_atomic_helper_check_plane_damage(state, new_plane_state);
> >  +
> >   	return 0;
> >   }
> >
> >  @@ -541,10 +550,20 @@ static void ingenic_drm_update_palette(struct 
> > ingenic_drm *priv,
> >   	}
> >   }
> >
> >  +void ingenic_drm_sync_data(struct device *dev,
> >  +			   struct drm_plane_state *old_state,
> >  +			   struct drm_plane_state *state)
> >  +{
> >  +	if (ingenic_drm_cached_gem_buf)
> >  +		drm_gem_cma_sync_data(dev, old_state, state);
> >  +}
> >  +
> >   static void ingenic_drm_plane_atomic_update(struct drm_plane 
> > *plane,
> >   					    struct drm_atomic_state *state)
> >   {
> >   	struct ingenic_drm *priv = drm_device_get_priv(plane->dev);
> >  +	struct drm_plane_state *oldstate = 
> > drm_atomic_get_old_plane_state(state,
> >  +									  plane);
> >   	struct drm_plane_state *newstate = 
> > drm_atomic_get_new_plane_state(state,
> >   									  plane);
> >   	struct drm_crtc_state *crtc_state;
> >  @@ -554,6 +573,8 @@ static void 
> > ingenic_drm_plane_atomic_update(struct drm_plane *plane,
> >   	u32 fourcc;
> >
> >   	if (newstate && newstate->fb) {
> >  +		ingenic_drm_sync_data(priv->dev, oldstate, newstate);
> >  +
> >   		crtc_state = newstate->crtc->state;
> >
> >   		addr = drm_fb_cma_get_gem_addr(newstate->fb, newstate, 0);
> >  @@ -743,6 +764,26 @@ static void ingenic_drm_disable_vblank(struct 
> > drm_crtc *crtc)
> >   	regmap_update_bits(priv->map, JZ_REG_LCD_CTRL, 
> > JZ_LCD_CTRL_EOF_IRQ, 0);
> >   }
> >
> >  +static struct drm_framebuffer *
> >  +ingenic_drm_gem_fb_create(struct drm_device *dev, struct drm_file 
> > *file,
> >  +			  const struct drm_mode_fb_cmd2 *mode_cmd)
> >  +{
> >  +	if (ingenic_drm_cached_gem_buf)
> >  +		return drm_gem_fb_create_with_dirty(dev, file, mode_cmd);
> >  +
> >  +	return drm_gem_fb_create(dev, file, mode_cmd);
> >  +}
> >  +
> >  +static int ingenic_drm_gem_cma_dumb_create(struct drm_file 
> > *file_priv,
> >  +					   struct drm_device *drm,
> >  +					   struct drm_mode_create_dumb *args)
> >  +{
> >  +	if (ingenic_drm_cached_gem_buf)
> >  +		return drm_gem_cma_dumb_create_noncoherent(file_priv, drm, args);
> >  +
> >  +	return drm_gem_cma_dumb_create(file_priv, drm, args);
> >  +}
> >  +
> >   DEFINE_DRM_GEM_CMA_FOPS(ingenic_drm_fops);
> >
> >   static const struct drm_driver ingenic_drm_driver_data = {
> >  @@ -755,7 +796,7 @@ static const struct drm_driver 
> > ingenic_drm_driver_data = {
> >   	.patchlevel		= 0,
> >
> >   	.fops			= &ingenic_drm_fops,
> >  -	DRM_GEM_CMA_DRIVER_OPS,
> >  
> > +	DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE(ingenic_drm_gem_cma_dumb_create),
> >
> >   	.irq_handler		= ingenic_drm_irq_handler,
> >   };
> >  @@ -805,7 +846,7 @@ static const struct drm_encoder_helper_funcs 
> > ingenic_drm_encoder_helper_funcs =
> >   };
> >
> >   static const struct drm_mode_config_funcs 
> > ingenic_drm_mode_config_funcs = {
> >  -	.fb_create		= drm_gem_fb_create,
> >  +	.fb_create		= ingenic_drm_gem_fb_create,
> >   	.output_poll_changed	= drm_fb_helper_output_poll_changed,
> >   	.atomic_check		= drm_atomic_helper_check,
> >   	.atomic_commit		= drm_atomic_helper_commit,
> >  @@ -962,6 +1003,8 @@ static int ingenic_drm_bind(struct device 
> > *dev, bool has_components)
> >   		return ret;
> >   	}
> >
> >  +	drm_plane_enable_fb_damage_clips(&priv->f1);
> >  +
> >   	drm_crtc_helper_add(&priv->crtc, &ingenic_drm_crtc_helper_funcs);
> >
> >   	ret = drm_crtc_init_with_planes(drm, &priv->crtc, primary,
> >  @@ -990,6 +1033,8 @@ static int ingenic_drm_bind(struct device 
> > *dev, bool has_components)
> >   			return ret;
> >   		}
> >
> >  +		drm_plane_enable_fb_damage_clips(&priv->f0);
> >  +
> >   		if (IS_ENABLED(CONFIG_DRM_INGENIC_IPU) && has_components) {
> >   			ret = component_bind_all(dev, drm);
> >   			if (ret) {
> >  diff --git a/drivers/gpu/drm/ingenic/ingenic-drm.h 
> > b/drivers/gpu/drm/ingenic/ingenic-drm.h
> >  index 1b4347f7f084..b6bca356e024 100644
> >  --- a/drivers/gpu/drm/ingenic/ingenic-drm.h
> >  +++ b/drivers/gpu/drm/ingenic/ingenic-drm.h
> >  @@ -185,6 +185,10 @@ void ingenic_drm_plane_config(struct device 
> > *dev,
> >   			      struct drm_plane *plane, u32 fourcc);
> >   void ingenic_drm_plane_disable(struct device *dev, struct 
> > drm_plane *plane);
> >
> >  +void ingenic_drm_sync_data(struct device *dev,
> >  +			   struct drm_plane_state *old_state,
> >  +			   struct drm_plane_state *state);
> >  +
> >   extern struct platform_driver *ingenic_ipu_driver_ptr;
> >
> >   #endif /* DRIVERS_GPU_DRM_INGENIC_INGENIC_DRM_H */
> >  diff --git a/drivers/gpu/drm/ingenic/ingenic-ipu.c 
> > b/drivers/gpu/drm/ingenic/ingenic-ipu.c
> >  index 5ae6adab8306..7826eab044ba 100644
> >  --- a/drivers/gpu/drm/ingenic/ingenic-ipu.c
> >  +++ b/drivers/gpu/drm/ingenic/ingenic-ipu.c
> >  @@ -20,6 +20,7 @@
> >
> >   #include <drm/drm_atomic.h>
> >   #include <drm/drm_atomic_helper.h>
> >  +#include <drm/drm_damage_helper.h>
> >   #include <drm/drm_drv.h>
> >   #include <drm/drm_fb_cma_helper.h>
> >   #include <drm/drm_fourcc.h>
> >  @@ -285,6 +286,8 @@ static void 
> > ingenic_ipu_plane_atomic_update(struct drm_plane *plane,
> >   					    struct drm_atomic_state *state)
> >   {
> >   	struct ingenic_ipu *ipu = plane_to_ingenic_ipu(plane);
> >  +	struct drm_plane_state *oldstate = 
> > drm_atomic_get_old_plane_state(state,
> >  +									  plane);
> >   	struct drm_plane_state *newstate = 
> > drm_atomic_get_new_plane_state(state,
> >   									  plane);
> >   	const struct drm_format_info *finfo;
> >  @@ -317,6 +320,8 @@ static void 
> > ingenic_ipu_plane_atomic_update(struct drm_plane *plane,
> >   				JZ_IPU_CTRL_CHIP_EN | JZ_IPU_CTRL_LCDC_SEL);
> >   	}
> >
> >  +	ingenic_drm_sync_data(ipu->master, oldstate, newstate);
> >  +
> >   	/* New addresses will be committed in vblank handler... */
> >   	ipu->addr_y = drm_fb_cma_get_gem_addr(newstate->fb, newstate, 0);
> >   	if (finfo->num_planes > 1)
> >  @@ -541,7 +546,7 @@ static int 
> > ingenic_ipu_plane_atomic_check(struct drm_plane *plane,
> >
> >   	if (!new_plane_state->crtc ||
> >   	    !crtc_state->mode.hdisplay || !crtc_state->mode.vdisplay)
> >  -		return 0;
> >  +		goto out_check_damage;
> >
> >   	/* Plane must be fully visible */
> >   	if (new_plane_state->crtc_x < 0 || new_plane_state->crtc_y < 0 ||
> >  @@ -558,7 +563,7 @@ static int 
> > ingenic_ipu_plane_atomic_check(struct drm_plane *plane,
> >   		return -EINVAL;
> >
> >   	if (!osd_changed(new_plane_state, old_plane_state))
> >  -		return 0;
> >  +		goto out_check_damage;
> >
> >   	crtc_state->mode_changed = true;
> >
> >  @@ -592,6 +597,9 @@ static int 
> > ingenic_ipu_plane_atomic_check(struct drm_plane *plane,
> >   	ipu->denom_w = denom_w;
> >   	ipu->denom_h = denom_h;
> >
> >  +out_check_damage:
> >  +	drm_atomic_helper_check_plane_damage(state, new_plane_state);
> >  +
> >   	return 0;
> >   }
> >
> >  @@ -773,6 +781,8 @@ static int ingenic_ipu_bind(struct device *dev, 
> > struct device *master, void *d)
> >   		return err;
> >   	}
> >
> >  +	drm_plane_enable_fb_damage_clips(plane);
> >  +
> >   	/*
> >   	 * Sharpness settings range is [0,32]
> >   	 * 0       : nearest-neighbor
> >  --
> >  2.30.1


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