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: Mikulas Patocka mpatocka@redhat.com Cc: stable@vger.kernel.org
--- drivers/gpu/drm/udl/udl_drv.h | 2 - drivers/gpu/drm/udl/udl_fb.c | 15 ++++++++------ drivers/gpu/drm/udl/udl_transfer.c | 39 ++++++++++++++++++------------------- 3 files changed, 30 insertions(+), 26 deletions(-)
Index: linux-4.17-rc7/drivers/gpu/drm/udl/udl_drv.h =================================================================== --- linux-4.17-rc7.orig/drivers/gpu/drm/udl/udl_drv.h 2018-06-03 13:15:01.000000000 +0200 +++ linux-4.17-rc7/drivers/gpu/drm/udl/udl_drv.h 2018-06-03 13:15:01.000000000 +0200 @@ -110,7 +110,7 @@ udl_fb_user_fb_create(struct drm_device 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); Index: linux-4.17-rc7/drivers/gpu/drm/udl/udl_fb.c =================================================================== --- linux-4.17-rc7.orig/drivers/gpu/drm/udl/udl_fb.c 2018-06-03 13:15:01.000000000 +0200 +++ linux-4.17-rc7/drivers/gpu/drm/udl/udl_fb.c 2018-06-03 13:15:01.000000000 +0200 @@ -91,7 +91,10 @@ int udl_handle_damage(struct udl_framebu 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; @@ -126,12 +129,12 @@ int udl_handle_damage(struct udl_framebu
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; } @@ -150,7 +153,7 @@ int udl_handle_damage(struct udl_framebu 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 */ Index: linux-4.17-rc7/drivers/gpu/drm/udl/udl_transfer.c =================================================================== --- linux-4.17-rc7.orig/drivers/gpu/drm/udl/udl_transfer.c 2018-06-03 13:15:01.000000000 +0200 +++ linux-4.17-rc7/drivers/gpu/drm/udl/udl_transfer.c 2018-06-03 13:15:01.000000000 +0200 @@ -83,12 +83,12 @@ static inline u16 pixel32_to_be16(const ((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 *
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;