[src/trunk]: src/sys/external/bsd/drm2 Disable the use of WC memory on Arm an...

[jmcneill <jmcneill%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b1df523b1d6c
branches:  trunk
changeset: 467286:b1df523b1d6c
user:      jmcneill <jmcneill%NetBSD.org@localhost>
date:      Sun Jan 19 12:03:27 2020 +0000

description:
Disable the use of WC memory on Arm and Arm64. From Linux:

 * The DRM driver stack is designed to work with cache coherent devices
 * only, but permits an optimization to be enabled in some cases, where
 * for some buffers, both the CPU and the GPU use uncached mappings,
 * removing the need for DMA snooping and allocation in the CPU caches.
 *
 * The use of uncached GPU mappings relies on the correct implementation
 * of the PCIe NoSnoop TLP attribute by the platform, otherwise the GPU
 * will use cached mappings nonetheless. On x86 platforms, this does not
 * seem to matter, as uncached CPU mappings will snoop the caches in any
 * case. However, on ARM and arm64, enabling this optimization on a
 * platform where NoSnoop is ignored results in loss of coherency, which
 * breaks correct operation of the device. Since we have no way of
 * detecting whether NoSnoop works or not, just disable this
 * optimization entirely for ARM and arm64.

diffstat:

 sys/external/bsd/drm2/dist/include/drm/drm_cache.h |   4 +++-
 sys/external/bsd/drm2/include/drm/drm_os_netbsd.h  |  10 +++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diffs (42 lines):

diff -r 293383533e4e -r b1df523b1d6c sys/external/bsd/drm2/dist/include/drm/drm_cache.h
--- a/sys/external/bsd/drm2/dist/include/drm/drm_cache.h        Sun Jan 19 11:29:42 2020 +0000
+++ b/sys/external/bsd/drm2/dist/include/drm/drm_cache.h        Sun Jan 19 12:03:27 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: drm_cache.h,v 1.2 2018/08/27 04:58:37 riastradh Exp $  */
+/*     $NetBSD: drm_cache.h,v 1.3 2020/01/19 12:03:27 jmcneill Exp $   */
 
 /**************************************************************************
  *
@@ -43,6 +43,8 @@
        return false;
 #elif defined(CONFIG_MIPS) && defined(CONFIG_CPU_LOONGSON3)
        return false;
+#elif defined(CONFIG_ARM) || defined(CONFIG_ARM64)
+       return false;
 #else
        return true;
 #endif
diff -r 293383533e4e -r b1df523b1d6c sys/external/bsd/drm2/include/drm/drm_os_netbsd.h
--- a/sys/external/bsd/drm2/include/drm/drm_os_netbsd.h Sun Jan 19 11:29:42 2020 +0000
+++ b/sys/external/bsd/drm2/include/drm/drm_os_netbsd.h Sun Jan 19 12:03:27 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: drm_os_netbsd.h,v 1.15 2019/11/05 23:29:28 jmcneill Exp $      */
+/*     $NetBSD: drm_os_netbsd.h,v 1.16 2020/01/19 12:03:27 jmcneill Exp $      */
 
 /*-
  * Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -41,6 +41,14 @@
 #define        CONFIG_X86_PAT  1
 #endif
 
+#if defined(__arm__)
+#define CONFIG_ARM     1
+#endif
+
+#if defined(__aarch64__)
+#define CONFIG_ARM64   1
+#endif
+
 /*
  * Nothing meaningfully depends on this; defining this avoids patching
  * away some conditionalization in drmP.h.