display: Put DCP to sleep if display is external

This stops DCP from killing our modeset if the connection cycles.

Also force a (potential) configure cycle if the display is external;
this makes sure updated stage2s will have a chance at fixing issues of
old stage1s. Modesetting is fast when it's the same mode as before.

Signed-off-by: Hector Martin <marcan@marcan.st>

proxyclient/m1n1/proxy.py

@@ -66,6 +66,11 @@ class EXC_RET(IntEnum):
     EXIT_GUEST = 3
     STEP = 4
 
+class DCP_SHUTDOWN_MODE(IntEnum):
+    QUIESCED = 0
+    SLEEP_IF_EXTERNAL = 1
+    SLEEP = 2
+
 ExcInfo = Struct(
     "regs" / Array(32, Int64ul),
     "spsr" / RegAdapter(SPSR),
@@ -1043,8 +1048,8 @@ class M1N1Proxy(Reloadable):
         return self.request(self.P_DISPLAY_INIT)
     def display_configure(self, cfg):
         return self.request(self.P_DISPLAY_CONFIGURE, cfg)
-    def display_shutdown(self):
-        return self.request(self.P_DISPLAY_SHUTDOWN)
+    def display_shutdown(self, mode):
+        return self.request(self.P_DISPLAY_SHUTDOWN, mode)
 
 __all__.extend(k for k, v in globals().items()
                if (callable(v) or isinstance(v, type)) and v.__module__ == __name__)

src/dcp.c

@@ -3,6 +3,7 @@
 #include "dcp.h"
 #include "adt.h"
 #include "malloc.h"
+#include "pmgr.h"
 #include "rtkit.h"
 #include "utils.h"
 
@@ -59,9 +60,14 @@ out_free:
     return NULL;
 }
 
-int dcp_shutdown(dcp_dev_t *dcp)
+int dcp_shutdown(dcp_dev_t *dcp, bool sleep)
 {
-    rtkit_quiesce(dcp->rtkit);
+    if (sleep) {
+        rtkit_sleep(dcp->rtkit);
+        pmgr_reset(0, "DISP0_CPU0");
+    } else {
+        rtkit_quiesce(dcp->rtkit);
+    }
     rtkit_free(dcp->rtkit);
     dart_shutdown(dcp->dart_disp);
     iovad_shutdown(dcp->iovad_dcp, dcp->dart_dcp);

src/dcp.h

@@ -17,6 +17,6 @@ typedef struct {
 
 dcp_dev_t *dcp_init(const char *dcp_path, const char *dcp_dart_path, const char *disp_dart_path);
 
-int dcp_shutdown(dcp_dev_t *dcp);
+int dcp_shutdown(dcp_dev_t *dcp, bool sleep);
 
 #endif

src/display.c

@@ -22,10 +22,11 @@
         continue;                                                                                  \
     }
 
-dcp_dev_t *dcp;
-dcp_iboot_if_t *iboot;
-u64 fb_dva;
-u64 fb_size;
+static dcp_dev_t *dcp;
+static dcp_iboot_if_t *iboot;
+static u64 fb_dva;
+static u64 fb_size;
+static bool display_is_external;
 
 #define abs(x) ((x) >= 0 ? (x) : -(x))
 
@@ -157,7 +158,7 @@ static uintptr_t display_map_fb(uintptr_t iova, u64 paddr, u64 size)
     return iova;
 }
 
-static int display_start_dcp(void)
+int display_start_dcp(void)
 {
     if (iboot)
         return 0;
@@ -185,14 +186,14 @@ static int display_start_dcp(void)
         fb_dva = display_map_fb(0, pa, size);
     if (!fb_dva) {
         printf("display: failed to find display DVA\n");
-        dcp_shutdown(dcp);
+        dcp_shutdown(dcp, false);
         return -1;
     }
 
     iboot = dcp_ib_init(dcp);
     if (!iboot) {
         printf("display: failed to initialize DCP iBoot interface\n");
-        dcp_shutdown(dcp);
+        dcp_shutdown(dcp, false);
         return -1;
     }
 
@@ -453,9 +454,24 @@ int display_configure(const char *config)
 
 int display_init(void)
 {
+    int node = adt_path_offset(adt, "/arm-io/disp0");
+
+    if (node < 0) {
+        printf("DISP0 node not found!\n");
+        return -1;
+    }
+
+    display_is_external = adt_getprop(adt, node, "external", NULL);
+    if (display_is_external)
+        printf("display: Display is external\n");
+    else
+        printf("display: Display is internal\n");
+
     if (cur_boot_args.video.width == 640 && cur_boot_args.video.height == 1136) {
         printf("display: Dummy framebuffer found, initializing display\n");
-
+        return display_configure(NULL);
+    } else if (display_is_external) {
+        printf("display: External display found, reconfiguring\n");
         return display_configure(NULL);
     } else {
         printf("display: Display is already initialized (%ldx%ld)\n", cur_boot_args.video.width,
@@ -464,11 +480,27 @@ int display_init(void)
     }
 }
 
-void display_shutdown(void)
+void display_shutdown(dcp_shutdown_mode mode)
 {
     if (iboot) {
         dcp_ib_shutdown(iboot);
-        dcp_shutdown(dcp);
+        switch (mode) {
+            case DCP_QUIESCED:
+                printf("display: Quiescing DCP (unconditional)\n");
+                dcp_shutdown(dcp, false);
+                break;
+            case DCP_SLEEP_IF_EXTERNAL:
+                if (!display_is_external)
+                    printf("display: Quiescing DCP (internal)\n");
+                else
+                    printf("display: Sleeping DCP (external)\n");
+                dcp_shutdown(dcp, display_is_external);
+                break;
+            case DCP_SLEEP:
+                printf("display: Sleeping DCP (unconditional)\n");
+                dcp_shutdown(dcp, true);
+                break;
+        }
         iboot = NULL;
     }
 }

src/display.h

@@ -3,8 +3,15 @@
 #ifndef DISPLAY_H
 #define DISPLAY_H
 
+typedef enum _dcp_shutdown_mode {
+    DCP_QUIESCED = 0,
+    DCP_SLEEP_IF_EXTERNAL = 1,
+    DCP_SLEEP = 2,
+} dcp_shutdown_mode;
+
 int display_init(void);
+int display_start_dcp(void);
 int display_configure(const char *config);
-void display_shutdown(void);
+void display_shutdown(dcp_shutdown_mode mode);
 
 #endif

src/hv.c

@@ -50,7 +50,9 @@ static struct hv_secondary_info_t hv_secondary_info;
 void hv_init(void)
 {
     pcie_shutdown();
-    display_shutdown();
+    // Make sure we wake up DCP if we put it to sleep, just quiesce it to match ADT
+    if (display_start_dcp() >= 0)
+        display_shutdown(DCP_QUIESCED);
     // reenable hpm interrupts for the guest for unused iodevs
     usb_hpm_restore_irqs(0);
     smp_start_secondaries();

src/main.c

@@ -132,9 +132,15 @@ void m1n1_main(void)
     gxf_init();
     mcc_init();
     mmu_init();
+    aic_init();
+    wdt_disable();
+    pmgr_init();
 
 #ifdef USE_FB
     display_init();
+    // Kick DCP to sleep, so dodgy monitors which cause reconnect cycles don't cause us to lose the
+    // framebuffer.
+    display_shutdown(DCP_SLEEP_IF_EXTERNAL);
     fb_init(false);
     fb_display_logo();
 #ifdef FB_SILENT_MODE
@@ -144,9 +150,6 @@ void m1n1_main(void)
 #endif
 #endif
 
-    aic_init();
-    wdt_disable();
-    pmgr_init();
     clk_init();
     cpufreq_init();
     sep_init();
@@ -164,7 +167,7 @@ void m1n1_main(void)
     nvme_shutdown();
     exception_shutdown();
     usb_iodev_shutdown();
-    display_shutdown();
+    display_shutdown(DCP_SLEEP_IF_EXTERNAL);
 #ifdef USE_FB
     fb_shutdown(next_stage.restore_logo);
 #endif

src/proxy.c

@@ -531,7 +531,7 @@ int proxy_process(ProxyRequest *request, ProxyReply *reply)
             reply->retval = display_configure((char *)request->args[0]);
             break;
         case P_DISPLAY_SHUTDOWN:
-            display_shutdown();
+            display_shutdown(request->args[0]);
             break;
 
         default: