x11-base/xorg-server/files/1.12.4-DRI2-Block-clients-on-VT-switch.patch

From c1696263ac372f2d0a02247e30787b710abb6a16 Mon Sep 17 00:00:00 2001
From: Daniel Kurtz <djkurtz@chromium.org>
Date: Sat, 27 Jul 2013 19:44:31 +0800
Subject: [PATCH] DRI2: Block clients on VT switch

Typically a DRM X11 video driver will drop DRM master on a VT switch to
enable multiple X servers.  Therefore any DRM IOCTLs issued by the driver
to process DRI2 commands will fail.

This patch copies the Block-client-on-VT-switch logic from GLXDRI2, where
it solves the exact same problem from clients using DRI2 via GLX.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>

v2: Unwrap EnterVT and LeaveVT on CloseScreen to avoid infinite recursion
on VT switch for server generation > 1.

BUG=chromium:220687,chromium:265051
TEST=Install developer image
  Login as guest
  Browse to www.youtube.com
  VT switch
  Wait 15 seconds
  VT switch back
  => User should NOT be logged out!
TEST=ssh to device
  stop ui
  X :1 &  # start a test X server
  DISPLAY=:1 xev &    # start a test X client
  kill %2             # kill test X client
  chvt 2              # VT-2 switch
  => No X server crash
---
 hw/xfree86/dri2/dri2.c    | 56 +++++++++++++++++++++++++++++++++++++
 hw/xfree86/dri2/dri2.h    |  3 ++
 hw/xfree86/dri2/dri2ext.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 129 insertions(+)

diff --git a/hw/xfree86/dri2/dri2.c b/hw/xfree86/dri2/dri2.c
index bca82d3..850e476 100644
--- a/hw/xfree86/dri2/dri2.c
+++ b/hw/xfree86/dri2/dri2.c
@@ -111,6 +111,9 @@ typedef struct _DRI2Screen {
     HandleExposuresProcPtr HandleExposures;
 
     ConfigNotifyProcPtr ConfigNotify;
+
+    xf86EnterVTProc *enterVT;
+    xf86LeaveVTProc *leaveVT;
 } DRI2ScreenRec;
 
 static DRI2ScreenPtr
@@ -1161,9 +1164,51 @@ DRI2ConfigNotify(WindowPtr pWin, int x, int y, int w, int h, int bw,
     return Success;
 }
 
+
+static Bool
+DRI2EnterVT(int index, int flags)
+{
+    ScrnInfoPtr scrn = xf86Screens[index];
+    ScreenPtr pScreen = screenInfo.screens[index];
+    DRI2ScreenPtr ds = DRI2GetScreen(pScreen);
+    Bool ret;
+
+    LogMessage(X_INFO, "DRI2: Resuming DRI2 clients after VT switch\n");
+
+    scrn->EnterVT = ds->enterVT;
+    ret = scrn->EnterVT(index, flags);
+    ds->enterVT = scrn->EnterVT;
+    scrn->EnterVT = DRI2EnterVT;
+
+    if (!ret)
+        return FALSE;
+
+    dri2ResumeClients();
+
+    return TRUE;
+}
+
+static void
+DRI2LeaveVT(int index, int flags)
+{
+    ScrnInfoPtr scrn = xf86Screens[index];
+    ScreenPtr pScreen = screenInfo.screens[index];
+    DRI2ScreenPtr ds = DRI2GetScreen(pScreen);
+
+    LogMessage(X_INFO, "DRI2: Suspending DRI2 clients for VT switch\n");
+
+    dri2SuspendClients();
+
+    scrn->LeaveVT = ds->leaveVT;
+    (*ds->leaveVT) (index, flags);
+    ds->leaveVT = scrn->LeaveVT;
+    scrn->LeaveVT = DRI2LeaveVT;
+}
+
 Bool
 DRI2ScreenInit(ScreenPtr pScreen, DRI2InfoPtr info)
 {
+    ScrnInfoPtr pScrn = xf86Screens[pScreen->myNum];
     DRI2ScreenPtr ds;
 
     const char *driverTypeNames[] = {
@@ -1268,6 +1313,12 @@ DRI2ScreenInit(ScreenPtr pScreen, DRI2InfoPtr info)
         }
     }
 
+    /* Wrap enter/leave VT callbacks */
+    ds->enterVT = pScrn->EnterVT;
+    pScrn->EnterVT = DRI2EnterVT;
+    ds->leaveVT = pScrn->LeaveVT;
+    pScrn->LeaveVT = DRI2LeaveVT;
+
     return TRUE;
 
  err_out:
@@ -1282,9 +1333,14 @@ void
 DRI2CloseScreen(ScreenPtr pScreen)
 {
     DRI2ScreenPtr ds = DRI2GetScreen(pScreen);
+    ScrnInfoPtr pScrn = xf86Screens[pScreen->myNum];
 
     pScreen->ConfigNotify = ds->ConfigNotify;
 
+    /* Unwrap enter/leave VT callbacks */
+    pScrn->EnterVT = ds->enterVT;
+    pScrn->LeaveVT = ds->leaveVT;
+
     free(ds->driverNames);
     free(ds);
     dixSetPrivate(&pScreen->devPrivates, dri2ScreenPrivateKey, NULL);
diff --git a/hw/xfree86/dri2/dri2.h b/hw/xfree86/dri2/dri2.h
index 06546bb..b10974d 100644
--- a/hw/xfree86/dri2/dri2.h
+++ b/hw/xfree86/dri2/dri2.h
@@ -313,4 +313,7 @@ extern _X_EXPORT void DRI2WaitMSCComplete(ClientPtr client, DrawablePtr pDraw,
                                           int frame, unsigned int tv_sec,
                                           unsigned int tv_usec);
 
+void dri2SuspendClients(void);
+void dri2ResumeClients(void);
+
 #endif
diff --git a/hw/xfree86/dri2/dri2ext.c b/hw/xfree86/dri2/dri2ext.c
index 2579a5c..96fc0fb 100644
--- a/hw/xfree86/dri2/dri2ext.c
+++ b/hw/xfree86/dri2/dri2ext.c
@@ -48,10 +48,62 @@
 
 /* The only xf86 include */
 #include "xf86Module.h"
+#include <xf86.h>
 
 static ExtensionEntry *dri2Extension;
 extern Bool DRI2ModuleSetup(void);
 
+static DevPrivateKeyRec dri2ClientPrivateKeyRec;
+
+#define dri2ClientPrivateKey (&dri2ClientPrivateKeyRec)
+
+static int dri2BlockClients;
+
+typedef struct DRI2ClientStateRec DRI2ClientState;
+
+/*
+** State kept per client.
+*/
+struct DRI2ClientStateRec {
+    /*
+     ** Whether this structure is currently being used to support a client.
+     */
+    Bool inUse;
+};
+
+static DRI2ClientState *
+dri2GetClient(ClientPtr pClient)
+{
+    return dixLookupPrivate(&pClient->devPrivates, dri2ClientPrivateKey);
+}
+
+void
+dri2SuspendClients(void)
+{
+    int i;
+
+    for (i = 1; i < currentMaxClients; i++) {
+        if (clients[i] && dri2GetClient(clients[i])->inUse)
+            IgnoreClient(clients[i]);
+    }
+
+    dri2BlockClients = TRUE;
+}
+
+void
+dri2ResumeClients(void)
+{
+    int i;
+
+    dri2BlockClients = FALSE;
+
+    for (i = 1; i < currentMaxClients; i++) {
+        if (clients[i] && dri2GetClient(clients[i])->inUse)
+            AttendClient(clients[i]);
+    }
+}
+
+
 static Bool
 validDrawable(ClientPtr client, XID drawable, Mask access_mode,
               DrawablePtr *pDrawable, int *status)
@@ -538,6 +590,20 @@ static int
 ProcDRI2Dispatch(ClientPtr client)
 {
     REQUEST(xReq);
+    DRI2ClientState *cl;
+
+    cl = dri2GetClient(client);
+    /* Mark it in use so we suspend it on VT switch. */
+    cl->inUse = TRUE;
+
+    /* If we're currently blocking DRI2 clients, just put this guy to
+     * sleep, reset the request and return. */
+    if (dri2BlockClients) {
+        ResetCurrentRequest(client);
+        client->sequence--;
+        IgnoreClient(client);
+        return Success;
+    }
 
     switch (stuff->data) {
     case X_DRI2QueryVersion:
@@ -622,6 +688,10 @@ int DRI2EventBase;
 static void
 DRI2ExtensionInit(void)
 {
+    if (!dixRegisterPrivateKey
+        (&dri2ClientPrivateKeyRec, PRIVATE_CLIENT, sizeof(DRI2ClientState)))
+        return;
+
     dri2Extension = AddExtension(DRI2_NAME,
                                  DRI2NumberEvents,
                                  DRI2NumberErrors,
-- 
1.8.3