temp/libcamera: Backport simple-pipeline buffer count patch

Which has already landed upstream. It has been observed to reduce frame drops in some situations, notably with the Pixel 3a rear camera.
2024-10-01 00:35:44 +02:00
2 changed files with 53 additions and 1 deletions
@@ -0,0 +1,50 @@
+From d3f0e40d49378a70405b975169ab444f4a565a17 Mon Sep 17 00:00:00 2001
+From: Robert Mader <robert.mader@collabora.com>
+Date: Thu, 26 Sep 2024 23:07:39 +0200
+Subject: [PATCH 5/5] pipeline: simple: Increase buffer count to four
+
+Which is not only what many other pipeline handlers use, but also a good
+lower limit when dealing with DRM and similar APIs. Even Mesas EGL and
+Vulkan WSI implementations use for the reason outlined in mesa commit
+992a2dbba80aba35efe83202e1013bd6143f0dba:
+> When the compositor is directly scanning out from the application's buffer it
+> may end up holding on to three buffers. These are the one that is is currently
+> scanning out from, one that has been given to DRM as the next buffer to flip
+> to, and one that has been attached and will be given to DRM as soon as the
+> previous flip completes. When we attach a fourth buffer to the compositor it
+> should replace that third buffer so we should get a release event immediately
+> after that. This patch therefore also changes the number of buffer slots to 4
+> so that we can accomodate that situation.
+
+Given the popularity of this buffer number the bump should be unlikely
+to cause problems. At the same time it may help with performance or
+even work around glitches.
+
+The previous number was introduced in commit
+a8964c28c80fb520ee3c7b10143371081d41405a without mentioning a specific
+reason against the change at hand.
+
+Signed-off-by: Robert Mader <robert.mader@collabora.com>
+Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
+Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
+Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
+---
+ src/libcamera/pipeline/simple/simple.cpp | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
+index 29320a26..b32f8b2c 100644
+--- a/src/libcamera/pipeline/simple/simple.cpp
+++ b/src/libcamera/pipeline/simple/simple.cpp
+@@ -1134,7 +1134,7 @@ CameraConfiguration::Status SimpleCameraConfiguration::validate()
+ 			cfg.frameSize = format.planes[0].size;
+ 		}
+ 
+-		cfg.bufferCount = 3;
+		cfg.bufferCount = 4;
+ 	}
+ 
+ 	return status;
+-- 
+2.46.2
+
@@ -3,7 +3,7 @@
 pkgname=libcamera
 pkgver=9999
 _pkgver=0.3.2
-pkgrel=6
+pkgrel=7
 pkgdesc="Linux camera framework"
 url="https://libcamera.org/"
 arch="all"
@@ -46,6 +46,7 @@ source="https://gitlab.freedesktop.org/camera/libcamera/-/archive/v$_pkgver/libc
 	0002-libcamera-simple-Force-disable-softwareISP-for-milli.patch
 	0003-libcamera-simple-Enable-softISP-for-the-Pinephone.patch
 	0004-libcamera-simple-Skip-hwISP-formats-if-swISP-is-acti.patch
+	0005-pipeline-simple-Increase-buffer-count-to-four.patch
 	qcam.desktop
 	90-libcamera.rules
 	"
@@ -150,6 +151,7 @@ ac7df3e4509ae874199810057f4d8416da71720c15534578cc352608a8ae228dfa4814f9eb995d55
 9b6da8bd11ff9d8400ed721fbbeb960ac8753c078fdd971d786a446a9f96fea19dfc55be2705dc44a152e11de996f88139c1d24637bffc257da5083d19fe80c9  0002-libcamera-simple-Force-disable-softwareISP-for-milli.patch
 0fc6a1108c4e905d2d422a664622dc25ec459f13765b5711ad009d4df0fd0cceda8cd067a18e5e54eb2346b292481952161e72deb03d416ba80b300256c25e40  0003-libcamera-simple-Enable-softISP-for-the-Pinephone.patch
 35c74746453f4c2e24a2185331afabcf64e3af01bec2462ec09940518cda0e91c4a1f33853b4b009e1f8352af3c606fbd4b4d3791ffbba0f610f19538380c4c8  0004-libcamera-simple-Skip-hwISP-formats-if-swISP-is-acti.patch
+b3ba41f81f30979e9b2bd41f5068cd720a11cde2e2a2e31a875493ad9e299cb3dd7b81b5862bea71201001533c6bde18e3d025f65df23e73af3b9363857654a2  0005-pipeline-simple-Increase-buffer-count-to-four.patch
 22167a4eceb6d1b40b0b7c45fdf116c71684f5340de7f767535cb8e160ad9d2ae0f00cb3d461f73a344520a48a4641cf46226841d78bee06bfbfd2a91337f754  qcam.desktop
 cb4eb19eec766f1b8667a8b7c9d5f7d44a2dce79fddfdf3b6e3d1849066cebe79f82566bdcf6659c7ddf4faaf233d5adac10cda636935785e5305e2b7e9b34a9  90-libcamera.rules
 "