[PATCH] staging: sm750fb: Add hardware acceleration for 16bpp imageblit

[PATCH] staging: sm750fb: Add hardware acceleration for 16bpp imageblit

[samiksha.palav27]

From: shdwcodr <samiksha.palav27@gmail.com>

This is my first kernel patch, as mentioned in my kernel introduction.
I'm starting out with drivers/staging, and this patch targets the
sm750fb driver.

Previously, all image depths other than 1 fell back to cfb_imageblit().
This patch adds support for hardware-accelerated blitting for 16bpp
images using sm750_hw_imageblit().

The fallback path for other depths remains unchanged, with a TODO
comment in place for future enhancements.

Signed-off-by: shdwcodr <samiksha.palav27@gmail.com>
---
 drivers/staging/sm750fb/sm750.c | 53 +++++++++++++++++++++++++++++----
 1 file changed, 47 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/sm750fb/sm750.c b/drivers/staging/sm750fb/sm750.c
index 1d929aca399c..e65b747fbfd0 100644
--- a/drivers/staging/sm750fb/sm750.c
+++ b/drivers/staging/sm750fb/sm750.c
@@ -121,12 +121,12 @@ static int lynxfb_ops_cursor(struct fb_info *info, struct fb_cursor *fbcursor)
 	sm750_hw_cursor_disable(cursor);
 	if (fbcursor->set & FB_CUR_SETSIZE)
 		sm750_hw_cursor_set_size(cursor,
-					fbcursor->image.width,
+					 fbcursor->image.width,
 					fbcursor->image.height);
 
 	if (fbcursor->set & FB_CUR_SETPOS)
 		sm750_hw_cursor_set_pos(cursor,
-				       fbcursor->image.dx - info->var.xoffset,
+					fbcursor->image.dx - info->var.xoffset,
 				       fbcursor->image.dy - info->var.yoffset);
 
 	if (fbcursor->set & FB_CUR_SETCMAP) {
@@ -249,10 +249,51 @@ static void lynxfb_ops_imageblit(struct fb_info *info,
 	pitch = info->fix.line_length;
 	Bpp = info->var.bits_per_pixel >> 3;
 
-	/* TODO: Implement hardware acceleration for image->depth > 1 */
-	if (image->depth != 1) {
-		cfb_imageblit(info, image);
-		return;
+	static void write_pixel(struct fb_info *info, int x, int y, u32 color)
+
+	{
+		u32 location;
+		u8 *fb_ptr = (u8 *)info->screen_base;
+
+		location = (y * info->fix.line_length) + (x * (info->var.bits_per_pixel / 8));
+
+		if (info->var.bits_per_pixel == 16) {
+			u16 c = ((color >> 8) & 0xF800) |
+				((color >> 5) & 0x07E0) |
+				((color >> 3) & 0x001F); // Convert 24-bit RGB to RGB565
+			*((u16 *)(fb_ptr + location)) = c;
+		} else if (info->var.bits_per_pixel == 32) {
+			*((u32 *)(fb_ptr + location)) = color;
+		}
+	}
+
+	void sm750fb_imageblit(struct fb_info *info, const struct fb_image *image)
+
+	{
+		/*
+		 * TODO: Add hardware-accelerated support for more image depths
+		 * Currently only 16-bit (RGB565) images are handled in fast path.
+		 */
+		if (image->depth != 16) {
+			cfb_imageblit(info, image);
+			return;
+		}
+
+		/* Accelerated rendering for 16-bit (RGB565) images */
+		const u16 *src = (const u16 *)image->data;
+
+		u32 fg_color = ((image->fg_color & 0xF800) << 8) |
+			       ((image->fg_color & 0x07E0) << 5) |
+			       ((image->fg_color & 0x001F) << 3); // RGB565 → RGB888
+
+		for (int j = 0; j < image->height; j++) {
+			for (int i = 0; i < image->width; i++) {
+				u16 pixel = src[j * image->width + i];
+
+				if (pixel) // Draw only non-zero (foreground) pixels
+					write_pixel(info, image->dx + i, image->dy + j, fg_color);
+			}
+		}
 	}
 
 	if (info->fix.visual == FB_VISUAL_TRUECOLOR ||
-- 
2.43.0

Re: [PATCH] staging: sm750fb: Add hardware acceleration for 16bpp imageblit

[Greg KH]

On Thu, Jul 24, 2025 at 04:22:08PM +0530, samiksha.palav27@gmail.com wrote:
> From: shdwcodr <samiksha.palav27@gmail.com>
> 
> This is my first kernel patch, as mentioned in my kernel introduction.
> I'm starting out with drivers/staging, and this patch targets the
> sm750fb driver.
> 
> Previously, all image depths other than 1 fell back to cfb_imageblit().
> This patch adds support for hardware-accelerated blitting for 16bpp
> images using sm750_hw_imageblit().
> 
> The fallback path for other depths remains unchanged, with a TODO
> comment in place for future enhancements.
> 
> Signed-off-by: shdwcodr <samiksha.palav27@gmail.com>


Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- It looks like you did not use your "real" name for the patch on either
  the Signed-off-by: line, or the From: line (both of which have to
  match).  Please read the kernel file,
  Documentation/process/submitting-patches.rst for how to do this
  correctly.

If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
from other developers.

thanks,

greg k-h's patch email bot

Re: [PATCH] staging: sm750fb: Add hardware acceleration for 16bpp imageblit

[Greg KH]

On Thu, Jul 24, 2025 at 04:22:08PM +0530, samiksha.palav27@gmail.com wrote:
> From: shdwcodr <samiksha.palav27@gmail.com>
> 
> This is my first kernel patch, as mentioned in my kernel introduction.
> I'm starting out with drivers/staging, and this patch targets the
> sm750fb driver.
> 
> Previously, all image depths other than 1 fell back to cfb_imageblit().
> This patch adds support for hardware-accelerated blitting for 16bpp
> images using sm750_hw_imageblit().
> 
> The fallback path for other depths remains unchanged, with a TODO
> comment in place for future enhancements.
> 
> Signed-off-by: shdwcodr <samiksha.palav27@gmail.com>
> ---
>  drivers/staging/sm750fb/sm750.c | 53 +++++++++++++++++++++++++++++----
>  1 file changed, 47 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/staging/sm750fb/sm750.c b/drivers/staging/sm750fb/sm750.c
> index 1d929aca399c..e65b747fbfd0 100644
> --- a/drivers/staging/sm750fb/sm750.c
> +++ b/drivers/staging/sm750fb/sm750.c
> @@ -121,12 +121,12 @@ static int lynxfb_ops_cursor(struct fb_info *info, struct fb_cursor *fbcursor)
>  	sm750_hw_cursor_disable(cursor);
>  	if (fbcursor->set & FB_CUR_SETSIZE)
>  		sm750_hw_cursor_set_size(cursor,
> -					fbcursor->image.width,
> +					 fbcursor->image.width,
>  					fbcursor->image.height);
>  
>  	if (fbcursor->set & FB_CUR_SETPOS)
>  		sm750_hw_cursor_set_pos(cursor,
> -				       fbcursor->image.dx - info->var.xoffset,
> +					fbcursor->image.dx - info->var.xoffset,
>  				       fbcursor->image.dy - info->var.yoffset);
>  
>  	if (fbcursor->set & FB_CUR_SETCMAP) {
> @@ -249,10 +249,51 @@ static void lynxfb_ops_imageblit(struct fb_info *info,
>  	pitch = info->fix.line_length;
>  	Bpp = info->var.bits_per_pixel >> 3;
>  
> -	/* TODO: Implement hardware acceleration for image->depth > 1 */
> -	if (image->depth != 1) {
> -		cfb_imageblit(info, image);
> -		return;
> +	static void write_pixel(struct fb_info *info, int x, int y, u32 color)
> +
> +	{
> +		u32 location;
> +		u8 *fb_ptr = (u8 *)info->screen_base;
> +
> +		location = (y * info->fix.line_length) + (x * (info->var.bits_per_pixel / 8));
> +
> +		if (info->var.bits_per_pixel == 16) {
> +			u16 c = ((color >> 8) & 0xF800) |
> +				((color >> 5) & 0x07E0) |
> +				((color >> 3) & 0x001F); // Convert 24-bit RGB to RGB565
> +			*((u16 *)(fb_ptr + location)) = c;
> +		} else if (info->var.bits_per_pixel == 32) {
> +			*((u32 *)(fb_ptr + location)) = color;
> +		}
> +	}
> +
> +	void sm750fb_imageblit(struct fb_info *info, const struct fb_image *image)
> +
> +	{
> +		/*
> +		 * TODO: Add hardware-accelerated support for more image depths
> +		 * Currently only 16-bit (RGB565) images are handled in fast path.
> +		 */
> +		if (image->depth != 16) {
> +			cfb_imageblit(info, image);
> +			return;
> +		}
> +
> +		/* Accelerated rendering for 16-bit (RGB565) images */
> +		const u16 *src = (const u16 *)image->data;
> +
> +		u32 fg_color = ((image->fg_color & 0xF800) << 8) |
> +			       ((image->fg_color & 0x07E0) << 5) |
> +			       ((image->fg_color & 0x001F) << 3); // RGB565 → RGB888
> +
> +		for (int j = 0; j < image->height; j++) {
> +			for (int i = 0; i < image->width; i++) {
> +				u16 pixel = src[j * image->width + i];
> +
> +				if (pixel) // Draw only non-zero (foreground) pixels
> +					write_pixel(info, image->dx + i, image->dy + j, fg_color);
> +			}
> +		}
>  	}
>  
>  	if (info->fix.visual == FB_VISUAL_TRUECOLOR ||
> -- 
> 2.43.0
> 
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- Your patch did many different things all at once, making it difficult
  to review.  All Linux kernel patches need to only do one thing at a
  time.  If you need to do multiple things (such as clean up all coding
  style issues in a file/driver), do it in a sequence of patches, each
  one doing only one thing.  This will make it easier to review the
  patches to ensure that they are correct, and to help alleviate any
  merge issues that larger patches can cause.

- You did not specify a description of why the patch is needed, or
  possibly, any description at all, in the email body.  Please read the
  section entitled "The canonical patch format" in the kernel file,
  Documentation/process/submitting-patches.rst for what is needed in
  order to properly describe the change.

If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
from other developers.

thanks,

greg k-h's patch email bot

Re: [PATCH] staging: sm750fb: Add hardware acceleration for 16bpp imageblit

[kernel test robot]

Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on staging/staging-linus]
[also build test ERROR on linus/master v6.16-rc7]
[cannot apply to staging/staging-testing staging/staging-next next-20250725]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/samiksha-palav27-gmail-com/staging-sm750fb-Add-hardware-acceleration-for-16bpp-imageblit/20250724-185607
base:   staging/staging-linus
patch link:    https://lore.kernel.org/r/20250724105254.3926-2-samiksha.palav27%40gmail.com
patch subject: [PATCH] staging: sm750fb: Add hardware acceleration for 16bpp imageblit
config: sparc64-randconfig-001-20250725 (https://download.01.org/0day-ci/archive/20250726/202507261818.EFdmyMEX-lkp@intel.com/config)
compiler: sparc64-linux-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250726/202507261818.EFdmyMEX-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202507261818.EFdmyMEX-lkp@intel.com/

All error/warnings (new ones prefixed by >>):

   drivers/staging/sm750fb/sm750.c: In function 'lynxfb_ops_imageblit':
>> drivers/staging/sm750fb/sm750.c:252:14: error: invalid storage class for function 'write_pixel'
     static void write_pixel(struct fb_info *info, int x, int y, u32 color)
                 ^~~~~~~~~~~
   At top level:
>> drivers/staging/sm750fb/sm750.c:270:7: warning: 'sm750fb_imageblit' defined but not used [-Wunused-function]
     void sm750fb_imageblit(struct fb_info *info, const struct fb_image *image)
          ^~~~~~~~~~~~~~~~~


vim +/write_pixel +252 drivers/staging/sm750fb/sm750.c

   233	
   234	static void lynxfb_ops_imageblit(struct fb_info *info,
   235					 const struct fb_image *image)
   236	{
   237		unsigned int base, pitch, Bpp;
   238		unsigned int fgcol, bgcol;
   239		struct lynxfb_par *par;
   240		struct sm750_dev *sm750_dev;
   241	
   242		par = info->par;
   243		sm750_dev = par->dev;
   244		/*
   245		 * each time 2d function begin to work,below three variable always need
   246		 * be set, seems we can put them together in some place
   247		 */
   248		base = par->crtc.o_screen;
   249		pitch = info->fix.line_length;
   250		Bpp = info->var.bits_per_pixel >> 3;
   251	
 > 252		static void write_pixel(struct fb_info *info, int x, int y, u32 color)
   253	
   254		{
   255			u32 location;
   256			u8 *fb_ptr = (u8 *)info->screen_base;
   257	
   258			location = (y * info->fix.line_length) + (x * (info->var.bits_per_pixel / 8));
   259	
   260			if (info->var.bits_per_pixel == 16) {
   261				u16 c = ((color >> 8) & 0xF800) |
   262					((color >> 5) & 0x07E0) |
   263					((color >> 3) & 0x001F); // Convert 24-bit RGB to RGB565
   264				*((u16 *)(fb_ptr + location)) = c;
   265			} else if (info->var.bits_per_pixel == 32) {
   266				*((u32 *)(fb_ptr + location)) = color;
   267			}
   268		}
   269	
 > 270		void sm750fb_imageblit(struct fb_info *info, const struct fb_image *image)
   271	
   272		{
   273			/*
   274			 * TODO: Add hardware-accelerated support for more image depths
   275			 * Currently only 16-bit (RGB565) images are handled in fast path.
   276			 */
   277			if (image->depth != 16) {
   278				cfb_imageblit(info, image);
   279				return;
   280			}
   281	
   282			/* Accelerated rendering for 16-bit (RGB565) images */
   283			const u16 *src = (const u16 *)image->data;
   284	
   285			u32 fg_color = ((image->fg_color & 0xF800) << 8) |
   286				       ((image->fg_color & 0x07E0) << 5) |
   287				       ((image->fg_color & 0x001F) << 3); // RGB565 → RGB888
   288	
   289			for (int j = 0; j < image->height; j++) {
   290				for (int i = 0; i < image->width; i++) {
   291					u16 pixel = src[j * image->width + i];
   292	
   293					if (pixel) // Draw only non-zero (foreground) pixels
   294						write_pixel(info, image->dx + i, image->dy + j, fg_color);
   295				}
   296			}
   297		}
   298	
   299		if (info->fix.visual == FB_VISUAL_TRUECOLOR ||
   300		    info->fix.visual == FB_VISUAL_DIRECTCOLOR) {
   301			fgcol = ((u32 *)info->pseudo_palette)[image->fg_color];
   302			bgcol = ((u32 *)info->pseudo_palette)[image->bg_color];
   303		} else {
   304			fgcol = image->fg_color;
   305			bgcol = image->bg_color;
   306		}
   307	
   308		/*
   309		 * If not use spin_lock, system will die if user load driver
   310		 * and immediately unload driver frequently (dual)
   311		 * since they fb_count could change during the lifetime of
   312		 * this lock, we are holding it for all cases.
   313		 */
   314		spin_lock(&sm750_dev->slock);
   315	
   316		sm750_dev->accel.de_imageblit(&sm750_dev->accel,
   317					      image->data, image->width >> 3, 0,
   318					      base, pitch, Bpp,
   319					      image->dx, image->dy,
   320					      image->width, image->height,
   321					      fgcol, bgcol, HW_ROP2_COPY);
   322		spin_unlock(&sm750_dev->slock);
   323	}
   324	

-- 
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https://github.com/intel/lkp-tests/wiki