Re: hung bootup with "drm/radeon/kms: move radeon KMS on/off switch out of staging."

[Dave Airlie <airlied@gmail.com>]

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On Fri, Feb 5, 2010 at 7:00 PM, Ingo Molnar <mingo@elte.hu> wrote:
>
> * Dave Airlie <airlied@linux.ie> wrote:
>
>>
>> > If it now does not boot up if all its sub-options are enabled, even of some
>> > of those sub-options are new, does that count as a driver regression? Sure it
>> > does to me ...
>>
>> But it doesn't to anyone else under any reasonable meaning of the word
>> regression.
>
> There are reactions in this thread that contradict your 'anyone else' point.
>
>> The config option states
>> "Choose this option if you want kernel modesetting enabled by default,
>>           and you have a new enough userspace to support this. Running old
>>           userspaces with this enabled will cause pain."
>>
>> Will cause pain sounds painful to me, I can make it seem much worse if
>> you'd like.
>
> Except you are missing that the hang (and the first crash as well) happens on
> brand-new user-space just as much - not just on 'old userspaces'.
>
> The bugs i've triggered are independent of any user-space component - it
> happens with a fresh distro just as much.
>
> As i suggested before, at least the text should be updated to include what
> has been written about CONFIG_DRM_RADEON_KMS in this thread before:
>
>  > This is a completely new driver.  It's only part of the existing drm for
>  > compatibility reasons.  It requires an entirely different graphics stack
>  > above it and works very differently from the old drm stack.
>

Okay I've attached a patch with a revised Kconfig in it.

Does this sound more like reality?

Dave.

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From 0a0c28103e9abf77ac6cf579821e51557f0194aa Mon Sep 17 00:00:00 2001
From: Dave Airlie <airlied@redhat.com>
Date: Fri, 5 Feb 2010 19:02:24 +1000
Subject: [PATCH] drm/radeon/kms: change Kconfig text to reflect the new option.

Ingo pointed out that we really don't give the user enough warning to make
a decision here. So revise the Kconfig text with a better warning.

Signed-off-by: Dave Airlie <airlied@redhat.com>
---
 drivers/gpu/drm/radeon/Kconfig |   12 ++++++++----
 1 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/radeon/Kconfig b/drivers/gpu/drm/radeon/Kconfig
index 5982321..1c02d23 100644
--- a/drivers/gpu/drm/radeon/Kconfig
+++ b/drivers/gpu/drm/radeon/Kconfig
@@ -1,10 +1,14 @@
 config DRM_RADEON_KMS
-	bool "Enable modesetting on radeon by default"
+	bool "Enable modesetting on radeon by default - NEW DRIVER"
 	depends on DRM_RADEON
 	help
-	  Choose this option if you want kernel modesetting enabled by default,
-	  and you have a new enough userspace to support this. Running old
-	  userspaces with this enabled will cause pain.
+	  Choose this option if you want kernel modesetting enabled by default.
+
+	  This is a completely new driver. It's only part of the existing drm
+	  for compatibility reasons. It requires an entirely different graphics
+	  stack above it and works very differently from the old drm stack.
+	  i.e. don't enable this unless you know what you are doing it may
+	  cause issues or bugs compared to the previous userspace driver stack.
 
 	  When kernel modesetting is enabled the IOCTL of radeon/drm
 	  driver are considered as invalid and an error message is printed
-- 
1.6.6