[PATCH v5 11/13] video: Use VIDEO_DAMAGE for VIDEO_COPY
Simon Glass
sjg at chromium.org
Thu Aug 31 04:49:15 CEST 2023
Hi Alper,
On Wed, 30 Aug 2023 at 13:07, Alper Nebi Yasak <alpernebiyasak at gmail.com> wrote:
>
> On 2023-08-21 23:06 +03:00, Alexander Graf wrote:
> >
> > On 21.08.23 21:11, Simon Glass wrote:
> >> Hi Alper,
> >>
> >> On Mon, 21 Aug 2023 at 07:51, Alper Nebi Yasak <alpernebiyasak at gmail.com> wrote:
> >>> From: Alexander Graf <agraf at csgraf.de>
> >>>
> >>> CONFIG_VIDEO_COPY implemented a range-based copying mechanism: If we
> >>> print a single character, it will always copy the full range of bytes
> >>> from the top left corner of the character to the lower right onto the
> >>> uncached frame buffer. This includes pretty much the full line contents
> >>> of the printed character.
> >>>
> >>> Since we now have proper damage tracking, let's make use of that to reduce
> >>> the amount of data we need to copy. With this patch applied, we will only
> >>> copy the tiny rectangle surrounding characters when we print them,
> >>> speeding up the video console.
> >> I suppose for rotated consoles it copies whole lines, but otherwise it
> >> does a lot of small copies?
> >
> >
> > I tried to keep the code as simple as possible and only track an "upper
> > left" and "lower right" corner of modifications. So sync will always
> > copy/flush a single rectangle.
>
> Yep, see patch 06/13 for size of the regions. E.g. for putc_xy()s it's
> fontdata->height * fontdata->width, for rows it's like fontdata->height
> * vid_priv->xsize * count...
>
> >>
> >>> After this, changes to the main frame buffer are not immediately copied
> >>> to the copy frame buffer, but postponed until the next video device
> >>> sync. So issue an explicit sync before inspecting the copy frame buffer
> >>> contents for the video tests.
> >> So how does the sync get done in this case?
> >
> > It gets called as part of video_sync():
> >
> > +static void video_flush_copy(struct udevice *vid)
> > +{
> > + struct video_priv *priv = dev_get_uclass_priv(vid);
> > +
> > + if (!priv->copy_fb)
> > + return;
> > +
> > + if (priv->damage.xend && priv->damage.yend) {
> > + int lstart = priv->damage.xstart * VNBYTES(priv->bpix);
> > + int lend = priv->damage.xend * VNBYTES(priv->bpix);
> > + int y;
> > +
> > + for (y = priv->damage.ystart; y < priv->damage.yend; y++) {
> > + ulong offset = (y * priv->line_length) + lstart;
> > + ulong len = lend - lstart;
> > +
> > + memcpy(priv->copy_fb + offset, priv->fb + offset, len);
> > + }
> > + }
> > +}
>
> I think Simon was asking how and when video_sync() is called outside the
> tests. The tests use lower-level functions that are ops->putc_xy() in
> each console, and normally vidconsole calls higher on the call-chain
> also maybe do a video_sync() when they think it's worth updating the
> display.
>
> >>
> >>> Signed-off-by: Alexander Graf <agraf at csgraf.de>
> >>> [Alper: Rebase for fontdata->height/w, fill_part(), fix memmove(dev),
> >>> drop from defconfig, use damage.xstart/yend, use IS_ENABLED(),
> >>> call video_sync() before copy_fb check, update video_copy test]
> >>> Co-developed-by: Alper Nebi Yasak <alpernebiyasak at gmail.com>
> >>> Signed-off-by: Alper Nebi Yasak <alpernebiyasak at gmail.com>
> >>> ---
> >>>
> >>> Changes in v5:
> >>> - Remove video_sync_copy() also from video_fill(), video_fill_part()
> >>> - Fix memmove() calls by removing the extra dev argument
> >>> - Call video_sync() before checking copy_fb in video tests
> >>> - Use xstart, ystart, xend, yend as names for damage region
> >>> - Use met->baseline instead of priv->baseline
> >>> - Use fontdata->height/width instead of VIDEO_FONT_HEIGHT/WIDTH
> >>> - Use xstart, ystart, xend, yend as names for damage region
> >>> - Use IS_ENABLED() instead of CONFIG_IS_ENABLED()
> >>> - Drop VIDEO_DAMAGE from sandbox defconfig added in a new patch
> >>> - Update dm_test_video_copy test added in a new patch
> >>>
> >>> Changes in v3:
> >>> - Make VIDEO_COPY always select VIDEO_DAMAGE
> >>>
> >>> Changes in v2:
> >>> - Add patch "video: Use VIDEO_DAMAGE for VIDEO_COPY"
> >>>
> >>> configs/sandbox_defconfig | 1 -
> >>> drivers/video/Kconfig | 5 ++
> >>> drivers/video/console_normal.c | 13 +----
> >>> drivers/video/console_rotate.c | 44 +++-----------
> >>> drivers/video/console_truetype.c | 16 +----
> >>> drivers/video/vidconsole-uclass.c | 16 -----
> >>> drivers/video/video-uclass.c | 97 ++++++++-----------------------
> >>> drivers/video/video_bmp.c | 7 ---
> >>> include/video.h | 37 ------------
> >>> include/video_console.h | 52 -----------------
> >>> test/dm/video.c | 3 +-
> >>> 11 files changed, 43 insertions(+), 248 deletions(-)
> >>>
> >>> diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
> >>> index 51b820f13121..259f31f26cee 100644
> >>> --- a/configs/sandbox_defconfig
> >>> +++ b/configs/sandbox_defconfig
> >>> @@ -307,7 +307,6 @@ CONFIG_USB_ETH_CDC=y
> >>> CONFIG_VIDEO=y
> >>> CONFIG_VIDEO_FONT_SUN12X22=y
> >>> CONFIG_VIDEO_COPY=y
> >>> -CONFIG_VIDEO_DAMAGE=y
> >>> CONFIG_CONSOLE_ROTATION=y
> >>> CONFIG_CONSOLE_TRUETYPE=y
> >>> CONFIG_CONSOLE_TRUETYPE_CANTORAONE=y
> >>> diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> >>> index 97f494a1340b..b3fbd9d7d9ca 100644
> >>> --- a/drivers/video/Kconfig
> >>> +++ b/drivers/video/Kconfig
> >>> @@ -83,11 +83,14 @@ config VIDEO_PCI_DEFAULT_FB_SIZE
> >>>
> >>> config VIDEO_COPY
> >>> bool "Enable copying the frame buffer to a hardware copy"
> >>> + select VIDEO_DAMAGE
> >>> help
> >>> On some machines (e.g. x86), reading from the frame buffer is very
> >>> slow because it is uncached. To improve performance, this feature
> >>> allows the frame buffer to be kept in cached memory (allocated by
> >>> U-Boot) and then copied to the hardware frame-buffer as needed.
> >>> + It uses the VIDEO_DAMAGE feature to keep track of regions to copy
> >>> + and will only copy actually touched regions.
> >>>
> >>> To use this, your video driver must set @copy_base in
> >>> struct video_uc_plat.
> >>> @@ -105,6 +108,8 @@ config VIDEO_DAMAGE
> >>> regions of the frame buffer that were modified before, speeding up
> >>> screen refreshes significantly.
> >>>
> >>> + It is also used by VIDEO_COPY to identify which regions changed.
> >>> +
> >>> config BACKLIGHT_PWM
> >>> bool "Generic PWM based Backlight Driver"
> >>> depends on BACKLIGHT && DM_PWM
> >>> diff --git a/drivers/video/console_normal.c b/drivers/video/console_normal.c
> >>> index a19ce6a2bc11..c44aa09473a3 100644
> >>> --- a/drivers/video/console_normal.c
> >>> +++ b/drivers/video/console_normal.c
> >>> @@ -35,10 +35,6 @@ static int console_set_row(struct udevice *dev, uint row, int clr)
> >>> fill_pixel_and_goto_next(&dst, clr, pbytes, pbytes);
> >>> end = dst;
> >>>
> >>> - ret = vidconsole_sync_copy(dev, line, end);
> >>> - if (ret)
> >>> - return ret;
> >>> -
> >>> video_damage(dev->parent,
> >>> 0,
> >>> fontdata->height * row,
> >>> @@ -57,14 +53,11 @@ static int console_move_rows(struct udevice *dev, uint rowdst,
> >>> void *dst;
> >>> void *src;
> >>> int size;
> >>> - int ret;
> >>>
> >>> dst = vid_priv->fb + rowdst * fontdata->height * vid_priv->line_length;
> >>> src = vid_priv->fb + rowsrc * fontdata->height * vid_priv->line_length;
> >>> size = fontdata->height * vid_priv->line_length * count;
> >>> - ret = vidconsole_memmove(dev, dst, src, size);
> >>> - if (ret)
> >>> - return ret;
> >>> + memmove(dst, src, size);
> >> Why are you making that change?
> >
> > There is no point in keeping a special vidconsole_memmove() around
> > anymore, since we don't actually need to call vidconsole_sync_copy()
> > after the move. The damage call that we introduced to all call sites in
> > combination with a video_sync() call takes over the job of the sync copy.
>
> More specifically, this batches the copying work video_sync_copy() does
> per console-op into video_flush_copy() called once per video_sync().
> Then, since vidconsole_memmove() is only used to memmove() and invoke
> that copy mechanism, we can also reduce it to just memmove().
OK, thank you.
Regards,
Simon
More information about the U-Boot
mailing list