From ad7cf9d75cfa6aee3e634e5fd177b52d015fa603 Mon Sep 17 00:00:00 2001 From: Paul Gofman Date: Mon, 26 Oct 2020 16:11:20 +0300 Subject: [PATCH] xf86drm.c: Use integer logarithm. log() is affected by FP control word and can provide inaccurate result. Fixes Killer Instinct under Wine not being able to find AMD vulkan device. Reviewed-by: Dave Airlie Signed-off-by: Paul Gofman --- xf86drm.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/xf86drm.c b/xf86drm.c index 50a6f09..dbb7c14 100644 --- a/xf86drm.c +++ b/xf86drm.c @@ -124,6 +124,22 @@ static drmServerInfoPtr drm_server_info; static bool drmNodeIsDRM(int maj, int min); static char *drmGetMinorNameForFD(int fd, int type); +static unsigned log2_int(unsigned x) +{ + unsigned l; + + if (x < 2) { + return 0; + } + for (l = 2; ; l++) { + if ((unsigned)(1 << l) > x) { + return l - 1; + } + } + return 0; +} + + drm_public void drmSetServerInfo(drmServerInfoPtr info) { drm_server_info = info; @@ -4001,7 +4017,7 @@ static void drmFoldDuplicatedDevices(drmDevicePtr local_devices[], int count) for (j = i + 1; j < count; j++) { if (drmDevicesEqual(local_devices[i], local_devices[j])) { local_devices[i]->available_nodes |= local_devices[j]->available_nodes; - node_type = log2(local_devices[j]->available_nodes); + node_type = log2_int(local_devices[j]->available_nodes); memcpy(local_devices[i]->nodes[node_type], local_devices[j]->nodes[node_type], drmGetMaxNodeName()); drmFreeDevice(&local_devices[j]); -- 2.7.4