From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
To: Douglas Anderson <dianders@chromium.org>
Cc: dri-devel@lists.freedesktop.org,
Linus Walleij <linus.walleij@linaro.org>,
lvzhaoxiong@huaqin.corp-partner.google.com,
Jani Nikula <jani.nikula@linux.intel.com>,
Hsin-Yi Wang <hsinyi@google.com>,
Javier Martinez Canillas <javierm@redhat.com>,
Neil Armstrong <neil.armstrong@linaro.org>,
Joel Selvaraj <jo@jsfamily.in>,
Cong Yang <yangcong5@huaqin.corp-partner.google.com>,
Sam Ravnborg <sam@ravnborg.org>, Daniel Vetter <daniel@ffwll.ch>,
David Airlie <airlied@gmail.com>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 3/8] drm/mipi-dsi: Reduce driver bloat of mipi_dsi_*_write_seq()
Date: Sat, 27 Apr 2024 05:05:14 +0300 [thread overview]
Message-ID: <CAA8EJpon4wAT8=U5t2pyzdDWDjY6651QyDSp0hJGn9WGks6-ug@mail.gmail.com> (raw)
In-Reply-To: <20240426165839.v2.3.Id15fae80582bc74a0d4f1338987fa375738f45b9@changeid>
On Sat, 27 Apr 2024 at 02:59, Douglas Anderson <dianders@chromium.org> wrote:
>
> Through a cooperative effort between Hsin-Yi Wang and Dmitry
> Baryshkov, we have realized the dev_err_ratelimited() in the
> mipi_dsi_*_write_seq() macros was causing quite a bit of bloat to the
> kernel. Let's hoist this call into drm_mipi_dsi.c by adding a "chatty"
> version of the functions that includes the print. While doing this,
> add a bit more comments to these macros making it clear that they
> print errors and also that they return out of _the caller's_ function.
>
> Without any changes to clients this gives a dramatic savings. Building
> with my build system shows one example:
>
> $ scripts/bloat-o-meter \
> .../before/panel-novatek-nt36672e.ko \
> .../after/panel-novatek-nt36672e.ko
>
> add/remove: 0/1 grow/shrink: 0/1 up/down: 0/-21496 (-21496)
> Function old new delta
> nt36672e_1080x2408_60hz_init._rs 10320 - -10320
> nt36672e_1080x2408_60hz_init 17412 6236 -11176
> Total: Before=32147, After=10651, chg -66.87%
>
> Note that given the change in location of the print it's harder to
> include the "cmd" in the printout for mipi_dsi_dcs_write_seq() since,
> theoretically, someone could call the new chatty function with a
> zero-size array and it would be illegal to dereference data[0].
> There's a printk format to print the whole buffer and this is probably
> more useful for debugging anyway. Given that we're doing this for
> mipi_dsi_dcs_write_seq(), let's also print the buffer for
> mipi_dsi_generic_write_seq() in the error case.
>
> It should be noted that the current consensus of DRM folks is that the
> mipi_dsi_*_write_seq() should be deprecated due to the non-intuitive
> return behavior. A future patch will formally mark them as deprecated
> and provide an alternative.
>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
>
> Changes in v2:
> - Add some comments to the macros about printing and returning.
> - Modify commit message now that this is part of a series.
> - Change the way err value is handled in prep for next patch.
> - Rebased upon patches to avoid theoretical int overflow.
>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
--
With best wishes
Dmitry
next prev parent reply other threads:[~2024-04-27 2:05 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-26 23:58 [PATCH v2 0/8] drm/mipi-dsi: Reduce bloat and add funcs for cleaner init seqs Douglas Anderson
2024-04-26 23:58 ` [PATCH v2 1/8] drm/mipi-dsi: Fix theoretical int overflow in mipi_dsi_dcs_write_seq() Douglas Anderson
2024-04-27 1:44 ` Dmitry Baryshkov
2024-04-27 6:22 ` Sam Ravnborg
2024-04-29 21:42 ` Doug Anderson
2024-04-26 23:58 ` [PATCH v2 2/8] drm/mipi-dsi: Fix theoretical int overflow in mipi_dsi_generic_write_seq() Douglas Anderson
2024-04-26 23:58 ` [PATCH v2 3/8] drm/mipi-dsi: Reduce driver bloat of mipi_dsi_*_write_seq() Douglas Anderson
2024-04-27 2:05 ` Dmitry Baryshkov [this message]
2024-04-26 23:58 ` [PATCH v2 4/8] drm/mipi-dsi: Introduce mipi_dsi_*_write_seq_multi() Douglas Anderson
2024-04-27 6:32 ` Sam Ravnborg
2024-04-29 14:13 ` Doug Anderson
2024-04-29 9:38 ` Neil Armstrong
2024-04-29 14:26 ` Doug Anderson
2024-04-29 15:39 ` Jani Nikula
2024-05-01 15:49 ` Doug Anderson
2024-05-01 15:57 ` Dmitry Baryshkov
2024-05-06 6:21 ` Linus Walleij
2024-04-26 23:58 ` [PATCH v2 5/8] drm/mipi-dsi: mipi_dsi_*_write functions don't need to ratelimit prints Douglas Anderson
2024-04-26 23:58 ` [PATCH v2 6/8] drm/panel: novatek-nt36672e: Switch to mipi_dsi_dcs_write_seq_multi() Douglas Anderson
2024-04-26 23:58 ` [PATCH v2 7/8] drm/panel: boe-tv101wum-nl6: Don't use a table for initting commands Douglas Anderson
2024-04-26 23:58 ` [PATCH v2 8/8] drm/panel: boe-tv101wum-nl6: Convert hex to lowercase Douglas Anderson
2024-04-27 8:48 ` Dmitry Baryshkov
2024-04-29 9:20 ` [PATCH v2 0/8] drm/mipi-dsi: Reduce bloat and add funcs for cleaner init seqs Jani Nikula
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