Date: Wed, 04 Mar 2009 14:09:19 -0500 From: Michael Butler <imb@protected-networks.net> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-current@freebsd.org Subject: Re: pci regression: "panic: resource_list_alloc: resource entry is busy" Message-ID: <49AED1DF.2060801@protected-networks.net> In-Reply-To: <200903041034.06931.jhb@freebsd.org> References: <49ADE16C.9030805@protected-networks.net> <200903041011.24606.jhb@freebsd.org> <200903041034.06931.jhb@freebsd.org>
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John Baldwin wrote:
> Probably at some point the agp and drm drivers for Intel will be merged which
> would fix this, but this patch should help for now. We used to be leaking
> a small portion of KVA due to this problem before.
>
> --- //depot/vendor/freebsd/src/sys/dev/pci/vga_pci.c 2008/09/19 19:15:30
> +++ //depot/user/jhb/acpipci/dev/pci/vga_pci.c 2009/03/04 15:32:08
> @@ -42,12 +42,20 @@
> #include <sys/bus.h>
> #include <sys/kernel.h>
> #include <sys/module.h>
> +#include <sys/rman.h>
> +#include <sys/systm.h>
>
> #include <dev/pci/pcireg.h>
> #include <dev/pci/pcivar.h>
>
> +struct vga_resource {
> + struct resource *vr_res;
> + int vr_refs;
> +};
> +
> struct vga_pci_softc {
> device_t vga_msi_child; /* Child driver using MSI. */
> + struct vga_resource vga_res[PCIR_MAX_BAR_0 + 1];
> };
>
> static int
> @@ -130,7 +138,27 @@
> vga_pci_alloc_resource(device_t dev, device_t child, int type, int *rid,
> u_long start, u_long end, u_long count, u_int flags)
> {
> + struct vga_pci_softc *sc;
> + int bar;
>
> + switch (type) {
> + case SYS_RES_MEMORY:
> + case SYS_RES_IOPORT:
> + /*
> + * For BARs, we cache the resource so that we only allocate it
> + * from the PCI bus once.
> + */
> + bar = PCI_RID2BAR(*rid);
> + if (bar < 0 || bar > PCIR_MAX_BAR_0)
> + return (NULL);
> + sc = device_get_softc(dev);
> + if (sc->vga_res[bar].vr_res == NULL)
> + sc->vga_res[bar].vr_res = bus_alloc_resource(dev, type,
> + rid, start, end, count, flags);
> + if (sc->vga_res[bar].vr_res != NULL)
> + sc->vga_res[bar].vr_refs++;
> + return (sc->vga_res[bar].vr_res);
> + }
> return (bus_alloc_resource(dev, type, rid, start, end, count, flags));
> }
>
> @@ -138,6 +166,37 @@
> vga_pci_release_resource(device_t dev, device_t child, int type, int rid,
> struct resource *r)
> {
> + struct vga_pci_softc *sc;
> + int bar, error;
> +
> + switch (type) {
> + case SYS_RES_MEMORY:
> + case SYS_RES_IOPORT:
> + /*
> + * For BARs, we release the resource from the PCI bus
> + * when the last child reference goes away.
> + */
> + bar = PCI_RID2BAR(rid);
> + if (bar < 0 || bar > PCIR_MAX_BAR_0)
> + return (EINVAL);
> + sc = device_get_softc(dev);
> + if (sc->vga_res[bar].vr_res == NULL)
> + return (EINVAL);
> + KASSERT(sc->vga_res[bar].vr_res == r,
> + ("vga_pci resource mismatch"));
> + if (sc->vga_res[bar].vr_refs > 1) {
> + sc->vga_res[bar].vr_refs--;
> + return (0);
> + }
> + KASSERT(sc->vga_res[bar].vr_refs > 0,
> + ("vga_pci resource reference count underflow"));
> + error = bus_release_resource(dev, type, rid, r);
> + if (error == 0) {
> + sc->vga_res[bar].vr_res = NULL;
> + sc->vga_res[bar].vr_refs = 0;
> + }
> + return (error);
> + }
>
> return (bus_release_resource(dev, type, rid, r));
> }
>
This works perfectly, thanks! :-)
Michael
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