2013/12/16 Daniel Vetter <daniel@xxxxxxxx>:
> 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.
Please take a look at arch/x86/kernel/setup.c, at the end of function
setup_arch:
#ifdef CONFIG_VT
#if defined(CONFIG_VGA_CONSOLE)
if (!efi_enabled(EFI_BOOT) || (efi_mem_type(0xa0000) !=
EFI_CONVENTIONAL_MEMORY))
conswitchp = &vga_con;
#elif defined(CONFIG_DUMMY_CONSOLE)
conswitchp = &dummy_con;
#endif
#endif
Shouldn't this code already be doing what you want on IVB? Perhaps we
could improve it to do what you want?
>>
>> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
>
> 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.
I teste the patch, it does the required magic to solve the remaining problem :)
> -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();
>> +
What if the dummy console is already in place? Shouldn't we somehow
take a look at the conswitchip variable or something like that?
Otherwise doing module_reload many times will make us load dummy_con
many times, no?
>> + 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");
(note: for some reason this patch doesn't apply directly on -nightly
due to differences on this chunk)
>> + 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@xxxxxxxxxxxxxxxxxxxxx
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
--
Paulo Zanoni
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