commit fcbd5b5a6ab5a05e3f539dbbbfbdd19ae3ce2ea7
parent 26ad9e73aae2ccf31702101a680a502d255c8701
Author: Kyle Milz <krwmilz@gmail.com>
Date: Thu, 18 Nov 2021 19:42:16 +0000
add README
Diffstat:
3 files changed, 25 insertions(+), 0 deletions(-)
diff --git a/README b/README
@@ -0,0 +1,17 @@
+The ATI Radeon HD4850M in my 2009 iMac 11,1 does not work with the
+Linux radeondrm stack. Although I use OpenBSD, it has the radeondrm(4)
+stack from Linux, and suffers the same problem. There are reports
+(https://bugs.freedesktop.org/show_bug.cgi?id=98046) of other people
+having the same problem too.
+
+Latest Release: 70 on July 20 2021
+Black screen: imac_radeondrm_atombios_encoders.diff
+Bad video: imac_radeondrm_display.diff
+Install: cd /sys/dev/pci/drm && patch < imac_radeondrm_*.diff</code>
+
+There are two distinct problems:
+
+ 1) The first problem is the display goes black when the radeondrm
+ code initializes the GPU.
+ 2) Once the first has been figured out, the video output is
+ corrupted resulting in strange rhythmic lines on the screen.
diff --git a/imac_radeondrm_atombios_encoders.diff b/imac_radeondrm_atombios_encoders.diff
@@ -1,3 +1,7 @@
+On my iMac 11,1 the main display stays dark without this diff. There was
+a similar change made for iMac 10,1 and I think there is some common Apple
+problem that is not expected by radeondrm.
+
Index: radeon/atombios_encoders.c
===================================================================
RCS file: /cvs/src/sys/dev/pci/drm/radeon/atombios_encoders.c,v
diff --git a/imac_radeondrm_display.diff b/imac_radeondrm_display.diff
@@ -1,3 +1,7 @@
+There is something wrong with the new PLL (phased lock loop) code that was
+introduced around 2012. This diff reverts the latest changes and works for
+me.
+
Index: radeon/radeon_display.c
===================================================================
RCS file: /cvs/src/sys/dev/pci/drm/radeon/radeon_display.c,v
