From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/drivers/pci/setup-res.c | 20 +++++++++++++++++++-
1 files changed, 19 insertions(+), 1 deletions(-)
diff --git a/kernel/drivers/pci/setup-res.c b/kernel/drivers/pci/setup-res.c
index d21fa04..875d50c 100644
--- a/kernel/drivers/pci/setup-res.c
+++ b/kernel/drivers/pci/setup-res.c
@@ -73,7 +73,8 @@
/*
* Apparently some Matrox devices have ROM BARs that read
* as zero when disabled, so don't update ROM BARs unless
- * they're enabled. See https://lkml.org/lkml/2005/8/30/138.
+ * they're enabled. See
+ * https://lore.kernel.org/r/43147B3D.1030309@vc.cvut.cz/
*/
if (!(res->flags & IORESOURCE_ROM_ENABLE))
return;
@@ -209,6 +210,17 @@
root = pci_find_parent_resource(dev, res);
if (!root) {
+ /*
+ * If dev is behind a bridge, accesses will only reach it
+ * if res is inside the relevant bridge window.
+ */
+ if (pci_upstream_bridge(dev))
+ return -ENXIO;
+
+ /*
+ * On the root bus, assume the host bridge will forward
+ * everything.
+ */
if (res->flags & IORESOURCE_IO)
root = &ioport_resource;
else
@@ -409,10 +421,16 @@
int pci_resize_resource(struct pci_dev *dev, int resno, int size)
{
struct resource *res = dev->resource + resno;
+ struct pci_host_bridge *host;
int old, ret;
u32 sizes;
u16 cmd;
+ /* Check if we must preserve the firmware's resource assignment */
+ host = pci_find_host_bridge(dev->bus);
+ if (host->preserve_config)
+ return -ENOTSUPP;
+
/* Make sure the resource isn't assigned before resizing it. */
if (!(res->flags & IORESOURCE_UNSET))
return -EBUSY;
--
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