Make it possible for graphics drivers to opt-out of VGA arbitration.

The idea is that as soon the kernel driver switches out of vga text
mode, it can disable decoding of legacy vga io and mmio and call
pci_disable_legacy_vga() to take itself out of arbitration.  The
PCIGETVGA ioctl is extended such that it returns the legacy decoding
state of a device.  The X server can then query this state for all
graphics devices in the system (through libpciaccess) and decide
whether it needs to do arbitration.

ok jsg@

2 files changed, 58 insertions, 38 deletions

diff --git a/sys/dev/pci/pci.c b/sys/dev/pci/pci.c
index 3a0a1570557..6a114f5d261 100644
--- a/sys/dev/pci/pci.c
+++ b/sys/dev/pci/pci.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pci.c,v 1.98 2013/02/09 20:43:33 miod Exp $	*/
+/*	$OpenBSD: pci.c,v 1.99 2013/08/08 17:54:11 kettenis Exp $	*/
 /*	$NetBSD: pci.c,v 1.31 1997/06/06 23:48:04 thorpej Exp $	*/
 
 /*
@@ -57,6 +57,7 @@ void pci_resume(struct pci_softc *);
 #define NMAPREG			((PCI_MAPREG_END - PCI_MAPREG_START) / \
 				    sizeof(pcireg_t))
 struct pci_dev {
+	struct device *pd_dev;
 	LIST_ENTRY(pci_dev) pd_next;
 	pcitag_t pd_tag;        /* pci register tag */
 	pcireg_t pd_csr;
@@ -69,6 +70,7 @@ struct pci_dev {
 	pcireg_t pd_msi_mau32;
 	pcireg_t pd_msi_md;
 	int pd_pmcsr_state;
+	int pd_vga_decode;
 };
 
 #ifdef APERTURE
@@ -88,7 +90,6 @@ int	pci_ndomains;
 struct proc *pci_vga_proc;
 struct pci_softc *pci_vga_pci;
 pcitag_t pci_vga_tag;
-int	pci_vga_count;
 
 int	pci_dopm;
 
@@ -102,7 +103,6 @@ int pci_enumerate_bus(struct pci_softc *,
     int (*)(struct pci_attach_args *), struct pci_attach_args *);
 #endif
 int	pci_reserve_resources(struct pci_attach_args *);
-int	pci_count_vga(struct pci_attach_args *);
 int	pci_primary_vga(struct pci_attach_args *);
 
 /*
@@ -191,9 +191,10 @@ pciattach(struct device *parent, struct device *self, void *aux)
 
 	pci_enumerate_bus(sc, pci_reserve_resources, NULL);
 
-	pci_enumerate_bus(sc, pci_count_vga, NULL);
+	/* Find the VGA device that's currently active. */
 	if (pci_enumerate_bus(sc, pci_primary_vga, NULL))
 		pci_vga_pci = sc;
+
 	pci_enumerate_bus(sc, NULL, NULL);
 }
 
@@ -401,7 +402,6 @@ pci_probe_device(struct pci_softc *sc, pcitag_t tag,
 	pci_chipset_tag_t pc = sc->sc_pc;
 	struct pci_attach_args pa;
 	struct pci_dev *pd;
-	struct device *dev;
 	pcireg_t id, class, intr, bhlcr, cap;
 	int pin, bus, device, function;
 	int off, ret = 0;
@@ -549,9 +549,16 @@ pci_probe_device(struct pci_softc *sc, pcitag_t tag,
 			pci_conf_write(pc, tag, PCI_COMMAND_STATUS_REG, csr);
 		splx(s);
 
-		if ((dev = config_found_sm(&sc->sc_dev, &pa, pciprint,
-		    pcisubmatch)))
-			pci_dev_postattach(dev, &pa);
+		if ((PCI_CLASS(class) == PCI_CLASS_DISPLAY &&
+		    PCI_SUBCLASS(class) == PCI_SUBCLASS_DISPLAY_VGA) ||
+		    (PCI_CLASS(class) == PCI_CLASS_PREHISTORIC &&
+		    PCI_SUBCLASS(class) == PCI_SUBCLASS_PREHISTORIC_VGA))
+			pd->pd_vga_decode = 1;
+
+		pd->pd_dev = config_found_sm(&sc->sc_dev, &pa, pciprint,
+		    pcisubmatch);
+		if (pd->pd_dev)
+			pci_dev_postattach(pd->pd_dev, &pa);
 	}
 
 	return (ret);
@@ -1016,6 +1023,25 @@ pci_matchbyid(struct pci_attach_args *pa, const struct pci_matchid *ids,
 	return (0);
 }
 
+void
+pci_disable_legacy_vga(struct device *dev)
+{
+	struct pci_softc *pci;
+	struct pci_dev *pd;
+
+	/* XXX Until we attach the drm drivers directly to pci. */
+	while (dev->dv_parent->dv_cfdata->cf_driver != &pci_cd)
+		dev = dev->dv_parent;
+
+	pci = (struct pci_softc *)dev->dv_parent;
+	LIST_FOREACH(pd, &pci->sc_devs, pd_next) {
+		if (pd->pd_dev == dev) {
+			pd->pd_vga_decode = 0;
+			break;
+		}
+	}
+}
+
 #ifdef USER_PCICONF
 /*
  * This is the user interface to PCI configuration space.
@@ -1259,20 +1285,32 @@ pciioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
 	case PCIOCGETVGA:
 	{
 		struct pci_vga *vga = (struct pci_vga *)data;
-		int bus, device, function;
+		struct pci_dev *pd;
+		int bus, dev, func;
 
-		pci_decompose_tag(pci_vga_pci->sc_pc, pci_vga_tag,
-		    &bus, &device, &function);
+		vga->pv_decode = 0;
+		LIST_FOREACH(pd, &pci->sc_devs, pd_next) {
+			pci_decompose_tag(pc, pd->pd_tag, NULL, &dev, &func);
+			if (dev == sel->pc_dev && func == sel->pc_func) {
+				if (pd->pd_vga_decode)
+					vga->pv_decode = PCI_VGA_IO_ENABLE |
+					    PCI_VGA_MEM_ENABLE;
+				break;
+			}
+		}
+
+		pci_decompose_tag(pci_vga_pci->sc_pc,
+		    pci_vga_tag, &bus, &dev, &func);
 		vga->pv_sel.pc_bus = bus;
-		vga->pv_sel.pc_dev = device;
-		vga->pv_sel.pc_func = function;
+		vga->pv_sel.pc_dev = dev;
+		vga->pv_sel.pc_func = func;
 		error = 0;
 		break;
 	}
 	case PCIOCSETVGA:
 	{
 		struct pci_vga *vga = (struct pci_vga *)data;
-		int bus, device, function;
+		int bus, dev, func;
 
 		switch (vga->pv_lock) {
 		case PCI_VGA_UNLOCK:
@@ -1301,11 +1339,10 @@ pciioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
 		}
 		pci_vga_proc = p;
 
-		pci_decompose_tag(pci_vga_pci->sc_pc, pci_vga_tag,
-		    &bus, &device, &function);
-		if (bus != vga->pv_sel.pc_bus ||
-		    device != vga->pv_sel.pc_dev ||
-		    function != vga->pv_sel.pc_func) {
+		pci_decompose_tag(pci_vga_pci->sc_pc,
+		    pci_vga_tag, &bus, &dev, &func);
+		if (bus != vga->pv_sel.pc_bus || dev != vga->pv_sel.pc_dev ||
+		    func != vga->pv_sel.pc_func) {
 			pci_disable_vga(pci_vga_pci->sc_pc, pci_vga_tag);
 			if (pci != pci_vga_pci) {
 				pci_unroute_vga(pci_vga_pci);
@@ -1382,24 +1419,6 @@ pci_unroute_vga(struct pci_softc *sc)
 #endif /* USER_PCICONF */
 
 int
-pci_count_vga(struct pci_attach_args *pa)
-{
-	/* XXX For now, only handle the first PCI domain. */
-	if (pa->pa_domain != 0)
-		return (0);
-
-	if ((PCI_CLASS(pa->pa_class) != PCI_CLASS_DISPLAY ||
-	    PCI_SUBCLASS(pa->pa_class) != PCI_SUBCLASS_DISPLAY_VGA) &&
-	    (PCI_CLASS(pa->pa_class) != PCI_CLASS_PREHISTORIC ||
-	    PCI_SUBCLASS(pa->pa_class) != PCI_SUBCLASS_PREHISTORIC_VGA))
-		return (0);
-
-	pci_vga_count++;
-
-	return (0);
-}
-
-int
 pci_primary_vga(struct pci_attach_args *pa)
 {
 	/* XXX For now, only handle the first PCI domain. */
diff --git a/sys/dev/pci/pcivar.h b/sys/dev/pci/pcivar.h
index 0fe08aaa9b0..fcd72371075 100644
--- a/sys/dev/pci/pcivar.h
+++ b/sys/dev/pci/pcivar.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pcivar.h,v 1.68 2013/08/07 07:29:19 mpi Exp $	*/
+/*	$OpenBSD: pcivar.h,v 1.69 2013/08/08 17:54:11 kettenis Exp $	*/
 /*	$NetBSD: pcivar.h,v 1.23 1997/06/06 23:48:05 thorpej Exp $	*/
 
 /*
@@ -245,6 +245,7 @@ struct pci_matchid {
 int pci_matchbyid(struct pci_attach_args *, const struct pci_matchid *, int);
 int pci_get_powerstate(pci_chipset_tag_t, pcitag_t);
 int pci_set_powerstate(pci_chipset_tag_t, pcitag_t, int);
+void pci_disable_legacy_vga(struct device *);
 
 /*
  * Vital Product Data (PCI 2.2)