[PATCH libdrm] libdrm: Fix issue about differrent domainID but same BDF

[Deng, Emily]

Ping ......

>-----Original Message-----
>From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Emily
>Deng
>Sent: Thursday, February 14, 2019 3:54 PM
>To: amd-gfx at lists.freedesktop.org
>Cc: Deng, Emily <Emily.Deng at amd.com>
>Subject: [PATCH libdrm] libdrm: Fix issue about differrent domainID but same
>BDF
>
>For multiple GPUs which has the same BDF, but has different domain ID, the
>drmOpenByBusid will return the wrong fd when startx.
>
>The reproduce sequence as below:
>1. Call drmOpenByBusid to open Card0, then will return the right fd0, and the
>fd0 is master privilege;
>2. Call drmOpenByBusid to open Card1. In function drmOpenByBusid, it will open
>Card0 first, this time, the fd1 for opening Card0 is not master privilege, and will
>call drmSetInterfaceVersion to identify the domain ID feature, as the fd1 is not
>master privilege, then drmSetInterfaceVersion will fail, and then won't compare
>domain ID, then return the wrong fd for Card1.
>
>Solution:
>First loop search the best match fd about drm 1.4.
>
>Signed-off-by: Emily Deng <Emily.Deng at amd.com>
>---
> xf86drm.c | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
>diff --git a/xf86drm.c b/xf86drm.c
>index 336d64d..b60e029 100644
>--- a/xf86drm.c
>+++ b/xf86drm.c
>@@ -584,11 +584,34 @@ static int drmOpenByBusid(const char *busid, int type)
>     if (base < 0)
>         return -1;
>
>+    /* We need to try for 1.4 first for proper PCI domain support */
>     drmMsg("drmOpenByBusid: Searching for BusID %s\n", busid);
>     for (i = base; i < base + DRM_MAX_MINOR; i++) {
>         fd = drmOpenMinor(i, 1, type);
>         drmMsg("drmOpenByBusid: drmOpenMinor returns %d\n", fd);
>         if (fd >= 0) {
>+            sv.drm_di_major = 1;
>+            sv.drm_di_minor = 4;
>+            sv.drm_dd_major = -1;        /* Don't care */
>+            sv.drm_dd_minor = -1;        /* Don't care */
>+            if (!drmSetInterfaceVersion(fd, &sv)) {
>+                buf = drmGetBusid(fd);
>+                drmMsg("drmOpenByBusid: drmGetBusid reports %s\n", buf);
>+                if (buf && drmMatchBusID(buf, busid, 1)) {
>+                    drmFreeBusid(buf);
>+                    return fd;
>+                }
>+                if (buf)
>+                    drmFreeBusid(buf);
>+            }
>+            close(fd);
>+        }
>+    }
>+
>+   for (i = base; i < base + DRM_MAX_MINOR; i++) {
>+        fd = drmOpenMinor(i, 1, type);
>+        drmMsg("drmOpenByBusid: drmOpenMinor returns %d\n", fd);
>+        if (fd >= 0) {
>             /* We need to try for 1.4 first for proper PCI domain support
>              * and if that fails, we know the kernel is busted
>              */
>--
>2.7.4
>
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