[PATCH 0/3] drm/format-helper: Support conversion to XRGB8888

[PATCH 0/3] drm/format-helper: Support conversion to XRGB8888

[Thomas Zimmermann]

(resending with dri-devel in cc)

Support conversion from RGB565 and RGB888 to XRGB8888. This enables
simpledrm to work with framebuffers of such formats.

UEFI and/or Grub will usually set 32-bit output in XRGB8888 format.
The issue can be reproduced by enabling simpledrm and requesting a
console framebuffer of different format on the kernel command line;
for example

  nomodeset video=1024x768-16

or

  nomodeset video=1024x768-24

Conversion helpers will do nothing in this case.

Make this work by implementing the rsp conversion helpers. Also add
a warning about unsupported format conversions. The patchset should
also enable odd userspace configurations, such as running Xorg with
16- or 24-bit color depth.

Thomas Zimmermann (3):
  drm/format-helper: Print warning on missing format conversion
  drm/format-helper: Add RGB888-to-XRGB8888 conversion
  drm/format-helper: Add RGB565-to-XRGB8888 conversion

 drivers/gpu/drm/drm_format_helper.c | 95 +++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)


base-commit: d97978df553d768e457cb68c637b2b0a6188b87c
-- 
2.35.1

[PATCH 1/3] drm/format-helper: Print warning on missing format conversion

[Thomas Zimmermann]

Not all possible format conversions are supported yet. Print a
warning on unsupported combinations.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/drm_format_helper.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index 0e7135114728..b648f29b21b6 100644
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -590,6 +590,9 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for
 		}
 	}
 
+	drm_warn_once(fb->dev, "No conversion helper from %p4cc to %p4cc found.\n",
+		      &fb_format, &dst_format);
+
 	return -EINVAL;
 }
 EXPORT_SYMBOL(drm_fb_blit_toio);
-- 
2.35.1

[PATCH 2/3] drm/format-helper: Add RGB888-to-XRGB8888 conversion

[Thomas Zimmermann]

Add a format helper that converts RGB888 to XRGB8888. Use this
function in drm_fb_blit_toio(). Fixes simpledrm output for this
combination of formats.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/drm_format_helper.c | 46 +++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index b648f29b21b6..c107ff75ef78 100644
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -411,6 +411,47 @@ void drm_fb_xrgb8888_to_rgb888_toio(void __iomem *dst, unsigned int dst_pitch,
 }
 EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb888_toio);
 
+static void drm_fb_rgb888_to_xrgb8888_line(void *dbuf, const void *sbuf, unsigned int pixels)
+{
+	u32 *dbuf32 = dbuf;
+	const u8 *sbuf8 = sbuf;
+	unsigned int x;
+
+	for (x = 0; x < pixels; x++) {
+		u8 r = *sbuf8++;
+		u8 g = *sbuf8++;
+		u8 b = *sbuf8++;
+		*dbuf32++ = 0xff000000 | (r << 16) | (g << 8) | b;
+	}
+}
+
+static void drm_fb_rgb888_to_xrgb8888_toio(void __iomem *dst, unsigned int dst_pitch,
+					   const void *vaddr, const struct drm_framebuffer *fb,
+					   const struct drm_rect *clip)
+{
+	size_t linepixels = clip->x2 - clip->x1;
+	size_t dst_len = linepixels * 4;
+	unsigned int y, lines = clip->y2 - clip->y1;
+	void *dbuf;
+
+	if (!dst_pitch)
+		dst_pitch = dst_len;
+
+	dbuf = kmalloc(dst_len, GFP_KERNEL);
+	if (!dbuf)
+		return;
+
+	vaddr += clip_offset(clip, fb->pitches[0], 3);
+	for (y = 0; y < lines; y++) {
+		drm_fb_rgb888_to_xrgb8888_line(dbuf, vaddr, linepixels);
+		memcpy_toio(dst, dbuf, dst_len);
+		vaddr += fb->pitches[0];
+		dst += dst_pitch;
+	}
+
+	kfree(dbuf);
+}
+
 static void drm_fb_xrgb8888_to_xrgb2101010_line(u32 *dbuf, const u32 *sbuf,
 						unsigned int pixels)
 {
@@ -583,6 +624,11 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for
 			drm_fb_xrgb8888_to_rgb888_toio(dst, dst_pitch, vmap, fb, clip);
 			return 0;
 		}
+	} else if (dst_format == DRM_FORMAT_XRGB8888) {
+		if (fb_format == DRM_FORMAT_RGB888) {
+			drm_fb_rgb888_to_xrgb8888_toio(dst, dst_pitch, vmap, fb, clip);
+			return 0;
+		}
 	} else if (dst_format == DRM_FORMAT_XRGB2101010) {
 		if (fb_format == DRM_FORMAT_XRGB8888) {
 			drm_fb_xrgb8888_to_xrgb2101010_toio(dst, dst_pitch, vmap, fb, clip);
-- 
2.35.1

[PATCH 3/3] drm/format-helper: Add RGB565-to-XRGB8888 conversion

[Thomas Zimmermann]

Add a format helper that converts RGB565 to XRGB8888. Use this
function in drm_fb_blit_toio(). Fixes simpledrm output for this
combination of formats.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/drm_format_helper.c | 46 +++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index c107ff75ef78..3b3b48ba5e85 100644
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -411,6 +411,49 @@ void drm_fb_xrgb8888_to_rgb888_toio(void __iomem *dst, unsigned int dst_pitch,
 }
 EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb888_toio);
 
+static void drm_fb_rgb565_to_xrgb8888_line(void *dbuf, const void *sbuf, unsigned int pixels)
+{
+	u32 *dbuf32 = dbuf;
+	const u16 *sbuf16 = sbuf;
+	unsigned int x;
+
+	for (x = 0; x < pixels; x++, ++sbuf16, ++dbuf32) {
+		u32 val32 = ((*sbuf16 & 0xf800) << 8) |
+			    ((*sbuf16 & 0x07e0) << 5) |
+			    ((*sbuf16 & 0x001f) << 3);
+		*dbuf32 = 0xff000000 | val32 |
+			  ((val32 >> 3) & 0x00070007) |
+			  ((val32 >> 2) & 0x00000300);
+	}
+}
+
+static void drm_fb_rgb565_to_xrgb8888_toio(void __iomem *dst, unsigned int dst_pitch,
+					   const void *vaddr, const struct drm_framebuffer *fb,
+					   const struct drm_rect *clip)
+{
+	size_t linepixels = clip->x2 - clip->x1;
+	size_t dst_len = linepixels * 4;
+	unsigned int y, lines = clip->y2 - clip->y1;
+	void *dbuf;
+
+	if (!dst_pitch)
+		dst_pitch = dst_len;
+
+	dbuf = kmalloc(dst_len, GFP_KERNEL);
+	if (!dbuf)
+		return;
+
+	vaddr += clip_offset(clip, fb->pitches[0], 2);
+	for (y = 0; y < lines; y++) {
+		drm_fb_rgb565_to_xrgb8888_line(dbuf, vaddr, linepixels);
+		memcpy_toio(dst, dbuf, dst_len);
+		vaddr += fb->pitches[0];
+		dst += dst_pitch;
+	}
+
+	kfree(dbuf);
+}
+
 static void drm_fb_rgb888_to_xrgb8888_line(void *dbuf, const void *sbuf, unsigned int pixels)
 {
 	u32 *dbuf32 = dbuf;
@@ -628,6 +671,9 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for
 		if (fb_format == DRM_FORMAT_RGB888) {
 			drm_fb_rgb888_to_xrgb8888_toio(dst, dst_pitch, vmap, fb, clip);
 			return 0;
+		} else if (fb_format == DRM_FORMAT_RGB565) {
+			drm_fb_rgb565_to_xrgb8888_toio(dst, dst_pitch, vmap, fb, clip);
+			return 0;
 		}
 	} else if (dst_format == DRM_FORMAT_XRGB2101010) {
 		if (fb_format == DRM_FORMAT_XRGB8888) {
-- 
2.35.1

Re: [PATCH 1/3] drm/format-helper: Print warning on missing format conversion

[Javier Martinez Canillas]

Hello Thomas,

On 4/21/22 20:17, Thomas Zimmermann wrote:
> Not all possible format conversions are supported yet. Print a
> warning on unsupported combinations.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

-- 
Best regards,

Javier Martinez Canillas
Linux Engineering
Red Hat

Re: [PATCH 2/3] drm/format-helper: Add RGB888-to-XRGB8888 conversion

[Javier Martinez Canillas]

On 4/21/22 20:17, Thomas Zimmermann wrote:
> Add a format helper that converts RGB888 to XRGB8888. Use this
> function in drm_fb_blit_toio(). Fixes simpledrm output for this
> combination of formats.
>

I think the examples you have in the cover letter are quite illustrative,
maybe I would mention an example in the commit description as well.

> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---

[snip]

> +
> +static void drm_fb_rgb888_to_xrgb8888_toio(void __iomem *dst, unsigned int dst_pitch,
> +					   const void *vaddr, const struct drm_framebuffer *fb,
> +					   const struct drm_rect *clip)
> +{
> +	size_t linepixels = clip->x2 - clip->x1;

drm_rect_width(clip) instead ?

> +	size_t dst_len = linepixels * 4;
> +	unsigned int y, lines = clip->y2 - clip->y1;
and drm_rect_height(clip) ?

> +	void *dbuf;
> +
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

-- 
Best regards,

Javier Martinez Canillas
Linux Engineering
Red Hat

Re: [PATCH 3/3] drm/format-helper: Add RGB565-to-XRGB8888 conversion

[Javier Martinez Canillas]

On 4/21/22 20:17, Thomas Zimmermann wrote:
> Add a format helper that converts RGB565 to XRGB8888. Use this
> function in drm_fb_blit_toio(). Fixes simpledrm output for this
> combination of formats.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>  drivers/gpu/drm/drm_format_helper.c | 46 +++++++++++++++++++++++++++++
>  1 file changed, 46 insertions(+)

Same comments than for patch 2/3.

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

-- 
Best regards,

Javier Martinez Canillas
Linux Engineering
Red Hat