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Commit 91ba11fb authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Dave Airlie
Browse files

udl-kms: avoid division 



Division is slow, so it shouldn't be done by the pixel generating code.
The driver supports only 2 or 4 bytes per pixel, so we can replace
division with a shift.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 09a00abe

drivers/gpu/drm/udl/udl_drv.h

+1 −1
Original line number Diff line number Diff line
@@ -112,7 +112,7 @@ udl_fb_user_fb_create(struct drm_device *dev, 
		      struct drm_file *file,

		      const struct drm_mode_fb_cmd2 *mode_cmd);



int udl_render_hline(struct drm_device *dev, int bpp, struct urb **urb_ptr,

int udl_render_hline(struct drm_device *dev, int log_bpp, struct urb **urb_ptr,

		     const char *front, char **urb_buf_ptr,

		     u32 byte_offset, u32 device_byte_offset, u32 byte_width,

		     int *ident_ptr, int *sent_ptr);

drivers/gpu/drm/udl/udl_fb.c

+9 −6
Original line number Diff line number Diff line
@@ -90,7 +90,10 @@ int udl_handle_damage(struct udl_framebuffer *fb, int x, int y, 
	int bytes_identical = 0;

	struct urb *urb;

	int aligned_x;

	int bpp = fb->base.format->cpp[0];

	int log_bpp;



	BUG_ON(!is_power_of_2(fb->base.format->cpp[0]));

	log_bpp = __ffs(fb->base.format->cpp[0]);



	if (!fb->active_16)

		return 0;
@@ -125,12 +128,12 @@ int udl_handle_damage(struct udl_framebuffer *fb, int x, int y, 


	for (i = y; i < y + height ; i++) {

		const int line_offset = fb->base.pitches[0] * i;

		const int byte_offset = line_offset + (x * bpp);

		const int dev_byte_offset = (fb->base.width * bpp * i) + (x * bpp);

		if (udl_render_hline(dev, bpp, &urb,

		const int byte_offset = line_offset + (x << log_bpp);

		const int dev_byte_offset = (fb->base.width * i + x) << log_bpp;

		if (udl_render_hline(dev, log_bpp, &urb,

				     (char *) fb->obj->vmapping,

				     &cmd, byte_offset, dev_byte_offset,

				     width * bpp,

				     width << log_bpp,

				     &bytes_identical, &bytes_sent))

			goto error;

	}
@@ -149,7 +152,7 @@ int udl_handle_damage(struct udl_framebuffer *fb, int x, int y, 
error:

	atomic_add(bytes_sent, &udl->bytes_sent);

	atomic_add(bytes_identical, &udl->bytes_identical);

	atomic_add(width*height*bpp, &udl->bytes_rendered);

	atomic_add((width * height) << log_bpp, &udl->bytes_rendered);

	end_cycles = get_cycles();

	atomic_add(((unsigned int) ((end_cycles - start_cycles)

		    >> 10)), /* Kcycles */

drivers/gpu/drm/udl/udl_transfer.c

+20 −19
Original line number Diff line number Diff line
@@ -83,12 +83,12 @@ static inline u16 pixel32_to_be16(const uint32_t pixel) 
		((pixel >> 8) & 0xf800));

}



static inline u16 get_pixel_val16(const uint8_t *pixel, int bpp)

static inline u16 get_pixel_val16(const uint8_t *pixel, int log_bpp)

{

	u16 pixel_val16 = 0;

	if (bpp == 2)

	u16 pixel_val16;

	if (log_bpp == 1)

		pixel_val16 = *(const uint16_t *)pixel;

	else if (bpp == 4)

	else

		pixel_val16 = pixel32_to_be16(*(const uint32_t *)pixel);

	return pixel_val16;

}
@@ -125,8 +125,9 @@ static void udl_compress_hline16( 
	const u8 *const pixel_end,

	uint32_t *device_address_ptr,

	uint8_t **command_buffer_ptr,

	const uint8_t *const cmd_buffer_end, int bpp)

	const uint8_t *const cmd_buffer_end, int log_bpp)

{

	const int bpp = 1 << log_bpp;

	const u8 *pixel = *pixel_start_ptr;

	uint32_t dev_addr  = *device_address_ptr;

	uint8_t *cmd = *command_buffer_ptr;
@@ -153,12 +154,12 @@ static void udl_compress_hline16( 
		raw_pixels_count_byte = cmd++; /*  we'll know this later */

		raw_pixel_start = pixel;



		cmd_pixel_end = pixel + min3(MAX_CMD_PIXELS + 1UL,

					(unsigned long)(pixel_end - pixel) / bpp,

					(unsigned long)(cmd_buffer_end - 1 - cmd) / 2) * bpp;

		cmd_pixel_end = pixel + (min3(MAX_CMD_PIXELS + 1UL,

					(unsigned long)(pixel_end - pixel) >> log_bpp,

					(unsigned long)(cmd_buffer_end - 1 - cmd) / 2) << log_bpp);



		prefetch_range((void *) pixel, cmd_pixel_end - pixel);

		pixel_val16 = get_pixel_val16(pixel, bpp);

		pixel_val16 = get_pixel_val16(pixel, log_bpp);



		while (pixel < cmd_pixel_end) {

			const u8 *const start = pixel;
@@ -170,7 +171,7 @@ static void udl_compress_hline16( 
			pixel += bpp;



			while (pixel < cmd_pixel_end) {

				pixel_val16 = get_pixel_val16(pixel, bpp);

				pixel_val16 = get_pixel_val16(pixel, log_bpp);

				if (pixel_val16 != repeating_pixel_val16)

					break;

				pixel += bpp;
@@ -179,10 +180,10 @@ static void udl_compress_hline16( 
			if (unlikely(pixel > start + bpp)) {

				/* go back and fill in raw pixel count */

				*raw_pixels_count_byte = (((start -

						raw_pixel_start) / bpp) + 1) & 0xFF;

						raw_pixel_start) >> log_bpp) + 1) & 0xFF;



				/* immediately after raw data is repeat byte */

				*cmd++ = (((pixel - start) / bpp) - 1) & 0xFF;

				*cmd++ = (((pixel - start) >> log_bpp) - 1) & 0xFF;



				/* Then start another raw pixel span */

				raw_pixel_start = pixel;
@@ -192,14 +193,14 @@ static void udl_compress_hline16( 


		if (pixel > raw_pixel_start) {

			/* finalize last RAW span */

			*raw_pixels_count_byte = ((pixel-raw_pixel_start) / bpp) & 0xFF;

			*raw_pixels_count_byte = ((pixel - raw_pixel_start) >> log_bpp) & 0xFF;

		} else {

			/* undo unused byte */

			cmd--;

		}



		*cmd_pixels_count_byte = ((pixel - cmd_pixel_start) / bpp) & 0xFF;

		dev_addr += ((pixel - cmd_pixel_start) / bpp) * 2;

		*cmd_pixels_count_byte = ((pixel - cmd_pixel_start) >> log_bpp) & 0xFF;

		dev_addr += ((pixel - cmd_pixel_start) >> log_bpp) * 2;

	}



	if (cmd_buffer_end <= MIN_RLX_CMD_BYTES + cmd) {
@@ -222,19 +223,19 @@ static void udl_compress_hline16( 
 * (that we can only write to, slowly, and can never read), and (optionally)

 * our shadow copy that tracks what's been sent to that hardware buffer.

 */

int udl_render_hline(struct drm_device *dev, int bpp, struct urb **urb_ptr,

int udl_render_hline(struct drm_device *dev, int log_bpp, struct urb **urb_ptr,

		     const char *front, char **urb_buf_ptr,

		     u32 byte_offset, u32 device_byte_offset,

		     u32 byte_width,

		     int *ident_ptr, int *sent_ptr)

{

	const u8 *line_start, *line_end, *next_pixel;

	u32 base16 = 0 + (device_byte_offset / bpp) * 2;

	u32 base16 = 0 + (device_byte_offset >> log_bpp) * 2;

	struct urb *urb = *urb_ptr;

	u8 *cmd = *urb_buf_ptr;

	u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;



	BUG_ON(!(bpp == 2 || bpp == 4));

	BUG_ON(!(log_bpp == 1 || log_bpp == 2));



	line_start = (u8 *) (front + byte_offset);

	next_pixel = line_start;
@@ -244,7 +245,7 @@ int udl_render_hline(struct drm_device *dev, int bpp, struct urb **urb_ptr, 


		udl_compress_hline16(&next_pixel,

			     line_end, &base16,

			     (u8 **) &cmd, (u8 *) cmd_end, bpp);

			     (u8 **) &cmd, (u8 *) cmd_end, log_bpp);



		if (cmd >= cmd_end) {

			int len = cmd - (u8 *) urb->transfer_buffer;