On 11/08/12 22:23, Jordan Justen wrote:
> Seems like you're going to need to:
> * Pull IoRead/Write16 from MdePkg/Library/BaseIoLibIntrinsic into the driver.
> * Rename to UnalignedIoRead/Write16 and remove the alignment assert
> * Read the BAR to get the address
> * Use UnalignedIoRead/Write16
Whoa, straight to the lowest level. But works fine. Adds gcc
dependency though. Incremental patch attached FYI.
thanks,
Gerd
From 3d38e9b451486b4df2e4e5ea6a223db240ffed86 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <[email protected]>
Date: Thu, 8 Nov 2012 23:07:57 +0100
Subject: [PATCH 2/2] unaligned access
---
OvmfPkg/QemuVideoDxe/Driver.c | 19 ++++++++++++++-----
1 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/OvmfPkg/QemuVideoDxe/Driver.c b/OvmfPkg/QemuVideoDxe/Driver.c
index ef7e521..0037997 100644
--- a/OvmfPkg/QemuVideoDxe/Driver.c
+++ b/OvmfPkg/QemuVideoDxe/Driver.c
@@ -550,6 +550,19 @@ outw (
);
}
+/*
+ * copy IoWrite16 from MdePkg/Library/BaseIoLibIntrinsic/IoLibGcc.c
+ * and drop alignment check
+ */
+VOID
+outw_unaligned (
+ IN UINTN Port,
+ IN UINT16 Value
+ )
+{
+ __asm__ __volatile__ ("outw %w0,%w1" : : "a" (Value), "d" ((UINT16)Port));
+}
+
/**
TODO: Add function description
@@ -795,12 +808,8 @@ bochsw (
Private->Variant = QEMU_VIDEO_BOCHS;
}
- /*
- * FIXME: VBE_DISPI_IOPORT_DATA is unaligned and writes catched
- * somewhere in the stack, so this doesn't actually work.
- */
outw (Private, VBE_DISPI_IOPORT_INDEX, Reg);
- outw (Private, VBE_DISPI_IOPORT_DATA, Data);
+ outw_unaligned (VBE_DISPI_IOPORT_DATA, Data);
}
VOID
--
1.7.1
------------------------------------------------------------------------------
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