From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 66BBFC761A6 for ; Thu, 30 Mar 2023 10:30:10 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 182A310EDA3; Thu, 30 Mar 2023 10:30:02 +0000 (UTC) Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by gabe.freedesktop.org (Postfix) with ESMTPS id DA61510EDA1; Thu, 30 Mar 2023 10:29:59 +0000 (UTC) Received: from eldfell (unknown [194.136.85.206]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: pq) by madras.collabora.co.uk (Postfix) with ESMTPSA id 254436603183; Thu, 30 Mar 2023 11:29:58 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1680172198; bh=vhjPj2kbm5Y+A7eBhdKagL7l5yP2aUIRVOpwAuAvMkU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=a+QEpWKjQf2mBR45mYJW5s5DVqXq36DpFolUyyDsF/NrifWl2ZnkgDh06z0z7RkMR SiGpykaCFzIEqZEv+tx+Dl04w6wBgzIIJ974o7korEgCBWbdNBIuehSdfhy1ZO8r5k OqARfU/dshCd89B6mWhw4+UOs9qmrqkz7igarMXXoWX5CtSOZ7DFTeqvqJDGm4O2GN Llh2R9XfQoEyYpQ+uGjJwovGISy47SwdcNw/qTFvD3XK5mjwtJlYJT0gpaXC5jP4jP oEat5Cb5MVb/plkG88EaVxQHUQCQ+K3+2nKKR+1PgmX8g619YpB5NV096gJVDc3i3M k8xmY5iVAzriQ== Date: Thu, 30 Mar 2023 13:29:54 +0300 From: Pekka Paalanen To: Ville Syrjala Message-ID: <20230330132954.42b1db21.pekka.paalanen@collabora.com> In-Reply-To: <20230321143643.26676-2-ville.syrjala@linux.intel.com> References: <20230321143643.26676-1-ville.syrjala@linux.intel.com> <20230321143643.26676-2-ville.syrjala@linux.intel.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.24; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Intel-gfx] [RFC][PATCH v2 1/3] drm: Introduce plane SIZE_HINTS property X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Simon Ser , intel-gfx@lists.freedesktop.org, Daniel Stone , Jonas =?UTF-8?B?w4VkYWhs?= , dri-devel@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Tue, 21 Mar 2023 16:36:41 +0200 Ville Syrjala wrote: > From: Ville Syrj=C3=A4l=C3=A4 >=20 > Add a new immutable plane property by which a plane can advertise > a handful of recommended plane sizes. This would be mostly exposed > by cursor planes as a slightly more capable replacement for > the DRM_CAP_CURSOR_WIDTH/HEIGHT caps, which can only declare > a one size fits all limit for the whole device. >=20 > Currently eg. amdgpu/i915/nouveau just advertize the max cursor > size via the cursor size caps. But always using the max sized > cursor can waste a surprising amount of power, so a better > stragey is desirable. >=20 > Most other drivers don't specify any cursor size at all, in > which case the ioctl code just claims that 64x64 is a great > choice. Whether that is actually true is debatable. >=20 > A poll of various compositor developers informs us that > blindly probing with setcursor/atomic ioctl to determine > suitable cursor sizes is not acceptable, thus the > introduction of the new property to supplant the cursor > size caps. The compositor will now be free to select a > more optimal cursor size from the short list of options. >=20 > The blob contains explicit min and max plane sizes, as > well as a 2D bitmap representing all the square and non-square > power of two sizes between the min and max. >=20 > Note that the reported sizes (either via the property or the > caps) make no claims about things such as plane scaling. So > these things should only really be consulted for simple > "cursor like" use cases. >=20 > v2: Try to add some docs > v3: Specify that value 0 is reserved for future use (basic idea from Jona= s) > Drop the note about typical hardware (Pekka) > v4: Total redesign to include the 2D bitmap >=20 > Cc: Simon Ser > Cc: Jonas =C3=85dahl > Cc: Daniel Stone > Cc: Pekka Paalanen > Signed-off-by: Ville Syrj=C3=A4l=C3=A4 > --- > drivers/gpu/drm/drm_mode_config.c | 7 +++ > drivers/gpu/drm/drm_plane.c | 96 +++++++++++++++++++++++++++++++ > include/drm/drm_mode_config.h | 5 ++ > include/drm/drm_plane.h | 6 ++ > include/uapi/drm/drm_mode.h | 29 ++++++++++ > 5 files changed, 143 insertions(+) >=20 > diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode= _config.c > index 87eb591fe9b5..21860f94a18c 100644 > --- a/drivers/gpu/drm/drm_mode_config.c > +++ b/drivers/gpu/drm/drm_mode_config.c > @@ -374,6 +374,13 @@ static int drm_mode_create_standard_properties(struc= t drm_device *dev) > return -ENOMEM; > dev->mode_config.modifiers_property =3D prop; > =20 > + prop =3D drm_property_create(dev, > + DRM_MODE_PROP_IMMUTABLE | DRM_MODE_PROP_BLOB, > + "SIZE_HINTS", 0); > + if (!prop) > + return -ENOMEM; > + dev->mode_config.size_hints_property =3D prop; > + > return 0; > } > =20 > diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c > index 24e7998d1731..fb9cee504767 100644 > --- a/drivers/gpu/drm/drm_plane.c > +++ b/drivers/gpu/drm/drm_plane.c > @@ -140,6 +140,27 @@ > * DRM_FORMAT_MOD_LINEAR. Before linux kernel release v5.1 there hav= e been > * various bugs in this area with inconsistencies between the capabi= lity > * flag and per-plane properties. > + * > + * SIZE_HINTS: > + * Blob property which contains the set of recommended plane size > + * which can used for simple "cursor like" use cases (eg. no scaling= ). > + * Using these hints frees userspace from extensive probing of > + * supported plane sizes through atomic/setcursor ioctls. > + * > + * For optimal usage userspace should pick the smallest size > + * that satisfies its own requirements. > + * > + * The blob contains explicit min/max sizes, as well as a 2D bitmap > + * representign all square and non-square POT sizes between. > + * > + * Drivers should only attach this property to planes that > + * support a very limited set of sizes. > + * > + * Note that property value 0 (ie. no blob) is reserved for potential > + * future use. Current userspace is expected to ignore the property > + * if the value is 0, and fall back to some other means (eg. > + * &DRM_CAP_CURSOR_WIDTH and &DRM_CAP_CURSOR_HEIGHT) to determine > + * the appropriate plane size to use. > */ > =20 > static unsigned int drm_num_planes(struct drm_device *dev) > @@ -1582,3 +1603,78 @@ int drm_plane_create_scaling_filter_property(struc= t drm_plane *plane, > return 0; > } > EXPORT_SYMBOL(drm_plane_create_scaling_filter_property); > + > +static int hint_dim(int x, int x0, int w, int min, int max) > +{ > + if (x =3D=3D 0) > + return min; > + else if (x =3D=3D w - 1) > + return max; > + else > + return 1 << (x0 + x); > +} > + > +/** > + * drm_plane_add_size_hint_property - create a size hint property > + * > + * @plane: drm plane > + * @min_width: minimum width > + * @min_height: minimum height > + * @max_width: maximum width > + * @max_height: maximum height > + * @cursor_size_ok: function to check if specified size is ok > + * > + * Create a size hints property for the plane. > + * > + * RETURNS: > + * Zero for success or -errno > + */ > +int drm_plane_add_size_hints_property(struct drm_plane *plane, > + int min_width, int min_height, > + int max_width, int max_height, > + bool (*size_ok)(struct drm_plane *plane, > + int width, int height)) > +{ > + struct drm_device *dev =3D plane->dev; > + struct drm_mode_config *config =3D &dev->mode_config; > + struct drm_property_blob *blob; > + struct drm_plane_size_hint *hints; > + int x, y, x0, y0, w, h; > + > + x0 =3D fls(min_width) - 1; > + y0 =3D fls(min_height) - 1; > + w =3D fls(2 * max_width - 1) - x0; > + h =3D fls(2 * max_height - 1) - y0; > + > + blob =3D drm_property_create_blob(dev, > + struct_size(hints, bitmap, > + DIV_ROUND_UP(w * h, 32)), > + NULL); > + if (IS_ERR(blob)) > + return PTR_ERR(blob); > + > + hints =3D blob->data; > + > + hints->min_width =3D min_width; > + hints->min_height =3D min_height; > + hints->max_width =3D max_width; > + hints->max_height =3D max_height; > + > + for (y =3D 0; y < h; y++) { > + int height =3D hint_dim(y, y0, h, min_height, max_height); > + > + for (x =3D 0; x < w; x++) { > + int width =3D hint_dim(x, x0, w, min_width, max_width); > + unsigned int bit =3D y * w + x; > + > + if (size_ok(plane, width, height)) > + hints->bitmap[bit/32] |=3D 1 << (bit & 31); > + } > + } > + > + drm_object_attach_property(&plane->base, config->size_hints_property, > + blob->base.id); > + > + return 0; > +} > +EXPORT_SYMBOL(drm_plane_add_size_hints_property); > diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h > index e5b053001d22..d5495c0804c5 100644 > --- a/include/drm/drm_mode_config.h > +++ b/include/drm/drm_mode_config.h > @@ -949,6 +949,11 @@ struct drm_mode_config { > */ > struct drm_property *modifiers_property; > =20 > + /** > + * @size_hints_propertty: Plane size hints property. > + */ > + struct drm_property *size_hints_property; > + > /* cursor size */ > uint32_t cursor_width, cursor_height; > =20 > diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h > index 51291983ea44..6d7326f15761 100644 > --- a/include/drm/drm_plane.h > +++ b/include/drm/drm_plane.h > @@ -32,6 +32,7 @@ > #include > =20 > struct drm_crtc; > +struct drm_plane_size_hint; > struct drm_printer; > struct drm_modeset_acquire_ctx; > =20 > @@ -945,5 +946,10 @@ drm_plane_get_damage_clips(const struct drm_plane_st= ate *state); > =20 > int drm_plane_create_scaling_filter_property(struct drm_plane *plane, > unsigned int supported_filters); > +int drm_plane_add_size_hints_property(struct drm_plane *plane, > + int min_width, int min_height, > + int max_width, int max_height, > + bool (*size_ok)(struct drm_plane *plane, > + int width, int height)); > =20 > #endif > diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h > index 46becedf5b2f..5a1de6bd80dd 100644 > --- a/include/uapi/drm/drm_mode.h > +++ b/include/uapi/drm/drm_mode.h > @@ -849,6 +849,35 @@ struct drm_color_lut { > __u16 reserved; > }; > =20 > +/** > + * struct drm_plane_size_hint - Plane size hints > + * > + * Includes a 2D bitmap in row major order of one bit per plane > + * size (WxH). The colums represent the possible plane widths as > + * ,, > + * the rows do the same for plane heights. The minimums and > + * maximums need not be power of two themselves. The bits > + * are walked in lsb->msb order. > + * > + * Example: > + * min_width =3D 33, min_height =3D 16 > + * max_width =3D 128, max_height =3D 127 > + * bitmap[0] =3D 0b100111011001 > + * 33 64 128 > + * 16 * > + * 32 * * > + * 64 * * * > + * 127 * > + * > + * Indicating support for 33x16,33xx32, > + * 64x32,64x64,128x64,128x127 sizes. > + */ > +struct drm_plane_size_hint { > + __u16 min_width, min_height; > + __u16 max_width, max_height; > + __u32 bitmap[]; > +}; Hi, as a compositor developer, I believe I could make use of this somehow. I would probably pose the optimization problem as "what dimensions result in the smallest area" in a compositor, iterating over the possible and allowed widths and checking the smallest possible and allowed height. If you think this is a good match to hardware capabilities, it's fine by me. The power-of-two is a pretty fundamental built-in assumption and I have no idea how good it is. Thanks, pq