Re: [PATCH v2 0/2] Fixes for omapdrm console

Thomas Zimmermann <tzimmermann@xxxxxxx> · Tue, 27 Feb 2024 12:34:28 +0100

Hi

Am 27.02.24 um 11:19 schrieb Tony Lindgren:
* Tony Lindgren <tony@xxxxxxxxxxx> [240227 11:47]:
* Thomas Zimmermann <tzimmermann@xxxxxxx> [240227 09:16]:
I just realized the fb_deferred_io_mmap() is already exported. So please use
it instead of duplicating the code in omapdrm.

[1] https://elixir.bootlin.com/linux/v6.7/source/drivers/video/fbdev/core/fb_defio.c#L237
Yeah I have now:

static int omap_fbdev_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
	vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));

	return fb_deferred_io_mmap(info, vma);
}

I also noticed that omapdrm does not yet select the correct Kconfig symbols.
That can be fixed by

  1) creating Kconfig FB_DMAMEM_HELPERS_DEFERRED that are similar to their
SYSMEM equivalent at [2]. The tokens should look like this

configFB_DMAMEM_HELPERS_DEFERRED  <https://elixir.bootlin.com/linux/latest/K/ident/CONFIG_FB_SYSMEM_HELPERS_DEFERRED>
bool
depends onFB_CORE  <https://elixir.bootlin.com/linux/latest/K/ident/CONFIG_FB_CORE>
selectFB_DEFERRED_IO  <https://elixir.bootlin.com/linux/latest/K/ident/CONFIG_FB_DEFERRED_IO>
selectFB_DMAMEM_HELPERS  <https://elixir.bootlin.com/linux/latest/K/ident/CONFIG_FB_SYSMEM_HELPERS>
OK

   2) and selecting it instead of FB_DMAMEM_HELPERS under omapdrm's Kconfig
symbol.
OK
So here's what I have now, does that look OK?

Looks good. You can add

Reviewed-by: Thomas Zimmermann <tzimmermann@xxxxxxx>

to the final patch.

Best regards
Thomas


Regards,

Tony

8< -------------------------

diff --git a/drivers/gpu/drm/omapdrm/Kconfig b/drivers/gpu/drm/omapdrm/Kconfig
--- a/drivers/gpu/drm/omapdrm/Kconfig
+++ b/drivers/gpu/drm/omapdrm/Kconfig
@@ -4,7 +4,7 @@ config DRM_OMAP
  	depends on DRM && OF
  	depends on ARCH_OMAP2PLUS
  	select DRM_KMS_HELPER
-	select FB_DMAMEM_HELPERS if DRM_FBDEV_EMULATION
+	select FB_DMAMEM_HELPERS_DEFERRED if DRM_FBDEV_EMULATION
  	select VIDEOMODE_HELPERS
  	select HDMI
  	default n
diff --git a/drivers/gpu/drm/omapdrm/omap_fbdev.c b/drivers/gpu/drm/omapdrm/omap_fbdev.c
--- a/drivers/gpu/drm/omapdrm/omap_fbdev.c
+++ b/drivers/gpu/drm/omapdrm/omap_fbdev.c
@@ -51,6 +51,10 @@ static void pan_worker(struct work_struct *work)
  	omap_gem_roll(bo, fbi->var.yoffset * npages);
  }
  
+FB_GEN_DEFAULT_DEFERRED_DMAMEM_OPS(omap_fbdev,
+				   drm_fb_helper_damage_range,
+				   drm_fb_helper_damage_area)
+
  static int omap_fbdev_pan_display(struct fb_var_screeninfo *var,
  		struct fb_info *fbi)
  {
@@ -78,11 +82,9 @@ static int omap_fbdev_pan_display(struct fb_var_screeninfo *var,
  
  static int omap_fbdev_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
  {
-	struct drm_fb_helper *helper = info->par;
-	struct drm_framebuffer *fb = helper->fb;
-	struct drm_gem_object *bo = drm_gem_fb_get_obj(fb, 0);
+	vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
  
-	return drm_gem_mmap_obj(bo, omap_gem_mmap_size(bo), vma);
+	return fb_deferred_io_mmap(info, vma);
  }
  
  static void omap_fbdev_fb_destroy(struct fb_info *info)
@@ -94,6 +96,7 @@ static void omap_fbdev_fb_destroy(struct fb_info *info)
  
  	DBG();
  
+	fb_deferred_io_cleanup(info);
  	drm_fb_helper_fini(helper);
  
  	omap_gem_unpin(bo);
@@ -104,15 +107,19 @@ static void omap_fbdev_fb_destroy(struct fb_info *info)
  	kfree(fbdev);
  }
  
+/*
+ * For now, we cannot use FB_DEFAULT_DEFERRED_OPS and fb_deferred_io_mmap()
+ * because we use write-combine.
+ */
  static const struct fb_ops omap_fb_ops = {
  	.owner = THIS_MODULE,
-	__FB_DEFAULT_DMAMEM_OPS_RDWR,
+	__FB_DEFAULT_DEFERRED_OPS_RDWR(omap_fbdev),
  	.fb_check_var	= drm_fb_helper_check_var,
  	.fb_set_par	= drm_fb_helper_set_par,
  	.fb_setcmap	= drm_fb_helper_setcmap,
  	.fb_blank	= drm_fb_helper_blank,
  	.fb_pan_display = omap_fbdev_pan_display,
-	__FB_DEFAULT_DMAMEM_OPS_DRAW,
+	__FB_DEFAULT_DEFERRED_OPS_DRAW(omap_fbdev),
  	.fb_ioctl	= drm_fb_helper_ioctl,
  	.fb_mmap	= omap_fbdev_fb_mmap,
  	.fb_destroy	= omap_fbdev_fb_destroy,
@@ -213,6 +220,15 @@ static int omap_fbdev_create(struct drm_fb_helper *helper,
  	fbi->fix.smem_start = dma_addr;
  	fbi->fix.smem_len = bo->size;
  
+	/* deferred I/O */
+	helper->fbdefio.delay = HZ / 20;
+	helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;
+
+	fbi->fbdefio = &helper->fbdefio;
+	ret = fb_deferred_io_init(fbi);
+	if (ret)
+		goto fail;
+
  	/* if we have DMM, then we can use it for scrolling by just
  	 * shuffling pages around in DMM rather than doing sw blit.
  	 */
diff --git a/drivers/video/fbdev/core/Kconfig b/drivers/video/fbdev/core/Kconfig
--- a/drivers/video/fbdev/core/Kconfig
+++ b/drivers/video/fbdev/core/Kconfig
@@ -144,6 +144,12 @@ config FB_DMAMEM_HELPERS
  	select FB_SYS_IMAGEBLIT
  	select FB_SYSMEM_FOPS
  
+config FB_DMAMEM_HELPERS_DEFERRED
+	bool
+	depends on FB_CORE
+	select FB_DEFERRED_IO
+	select FB_DMAMEM_HELPERS
+
  config FB_IOMEM_FOPS
  	tristate
  	depends on FB_CORE
diff --git a/include/linux/fb.h b/include/linux/fb.h
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -686,6 +686,10 @@ extern int fb_deferred_io_fsync(struct file *file, loff_t start,
  	__FB_GEN_DEFAULT_DEFERRED_OPS_RDWR(__prefix, __damage_range, sys) \
  	__FB_GEN_DEFAULT_DEFERRED_OPS_DRAW(__prefix, __damage_area, sys)
  
+#define FB_GEN_DEFAULT_DEFERRED_DMAMEM_OPS(__prefix, __damage_range, __damage_area) \
+	__FB_GEN_DEFAULT_DEFERRED_OPS_RDWR(__prefix, __damage_range, sys) \
+	__FB_GEN_DEFAULT_DEFERRED_OPS_DRAW(__prefix, __damage_area, sys)
+
  /*
   * Initializes struct fb_ops for deferred I/O.
   */

--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)








