[Intel-gfx] [PATCH] RFC hax: drm/i915: Kick out vga console

[Daniel Vetter]

On Mon, Dec 16, 2013 at 05:19:25PM +0000, Chris Wilson wrote:
> Touching the VGA resources on an IVB EFI machine causes hard hangs when
> we then kick out the efifb. Ouch.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

Like I've said on irc I think we want a select DUMMY_CONSOLE here, at
least if none of the core developers objects. And we also need this (or
something similar) to make Paulo happy, this should fix unclaimed register
disasters due to vgacon accessing the dead vga ranges when unloading our
driver on hsw while pc8/D3 is in effect.

Paulo, can you please give this a spin - you need to make sure that
CONFIG_DUMMY_CONSOLE is set though, so that needs some magic.
-Daniel

> ---
>  drivers/gpu/drm/i915/i915_dma.c  | 29 +++++++++++++++++++++++++++++
>  drivers/video/console/dummycon.c |  1 +
>  2 files changed, 30 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index 6de3a43e3acf..837d1a69ca52 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -36,6 +36,8 @@
>  #include "i915_drv.h"
>  #include "i915_trace.h"
>  #include <linux/pci.h>
> +#include <linux/console.h>
> +#include <linux/vt.h>
>  #include <linux/vgaarb.h>
>  #include <linux/acpi.h>
>  #include <linux/pnp.h>
> @@ -1444,6 +1446,27 @@ static int i915_kick_out_firmware_fb(struct drm_i915_private *dev_priv)
>  }
>  #endif
>  
> +static int i915_kick_out_vgacon(struct drm_i915_private *dev_priv)
> +{
> +	int ret;
> +
> +#if !defined(CONFIG_VGA_CONSOLE)
> +	return 0;
> +#endif
> +
> +#if !defined(CONFIG_DUMMY_CONSOLE)
> +	return -ENODEV;
> +#endif
> +
> +	DRM_INFO("Replacing VGA console driver\n");
> +
> +	console_lock();
> +	ret = do_take_over_console(&dummy_con, 0, MAX_NR_CONSOLES - 1, 1);
> +	console_unlock();
> +
> +	return ret;
> +}
> +
>  static void i915_dump_device_info(struct drm_i915_private *dev_priv)
>  {
>  	const struct intel_device_info *info = dev_priv->info;
> @@ -1557,6 +1580,12 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
>  		goto out_regs;
>  
>  	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> +		ret = i915_kick_out_vgacon(dev_priv);
> +		if (ret) {
> +			DRM_ERROR("failed to remove conflicting VGA console\n");
> +			goto out_gtt;
> +		}
> +
>  		ret = i915_kick_out_firmware_fb(dev_priv);
>  		if (ret) {
>  			DRM_ERROR("failed to remove conflicting framebuffer drivers\n");
> diff --git a/drivers/video/console/dummycon.c b/drivers/video/console/dummycon.c
> index b63860f7beab..40bec8d64b0a 100644
> --- a/drivers/video/console/dummycon.c
> +++ b/drivers/video/console/dummycon.c
> @@ -77,3 +77,4 @@ const struct consw dummy_con = {
>      .con_set_palette =	DUMMY,
>      .con_scrolldelta =	DUMMY,
>  };
> +EXPORT_SYMBOL_GPL(dummy_con);
> -- 
> 1.8.5.1
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch