[v3,2/2] drm/omapdrm: Fix console with deferred ops

Commit Message

Tony Lindgren Feb. 28, 2024, 6:35 a.m. UTC

Commit 95da53d63dcf ("drm/omapdrm: Use regular fbdev I/O helpers")
stopped console from updating for command mode displays because there is
no damage handling in fb_sys_write() unlike we had earlier in
drm_fb_helper_sys_write().

Let's fix the issue by adding FB_GEN_DEFAULT_DEFERRED_DMAMEM_OPS and
FB_DMAMEM_HELPERS_DEFERRED as suggested by Thomas. We cannot use the
FB_DEFAULT_DEFERRED_OPS as fb_deferred_io_mmap() won't work properly
for write-combine.

Fixes: 95da53d63dcf ("drm/omapdrm: Use regular fbdev I/O helpers")
Suggested-by: Thomas Zimmermann <[e-mail]>
Reviewed-by: Thomas Zimmermann <[e-mail]>
Signed-off-by: Tony Lindgren <[e-mail]>
---
 drivers/gpu/drm/omapdrm/Kconfig      |  2 +-
 drivers/gpu/drm/omapdrm/omap_fbdev.c | 28 ++++++++++++++++++++++------
 drivers/video/fbdev/core/Kconfig     |  6 ++++++
 include/linux/fb.h                   |  4 ++++
 4 files changed, 33 insertions(+), 7 deletions(-)

Patch

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.
  */