From: Emil Velikov <emil.l.velikov@gmail.com>
To: Jani Nikula <jani.nikula@linux.intel.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-gfx@lists.freedesktop.org, kernel@collabora.com,
dri-devel@lists.freedesktop.org
Subject: [Intel-gfx] [PATCH] drm/i915: apply WaEnableVGAAccessThroughIOPort as needed
Date: Fri, 4 Jun 2021 16:49:05 +0100 [thread overview]
Message-ID: <20210604154905.660142-1-emil.l.velikov@gmail.com> (raw)
From: Emil Velikov <emil.velikov@collabora.com>
Currently as the workaround is applied the screen flickers. As a result
we do not achieve seamless boot experience.
Avoiding the issue in the common use-case might be hard, although we can
resolve it for dual GPU setups - when the "other" GPU is primary and/or
outputs are connected to it.
With this I was able to get seamless experience on my Intel/Nvidia box,
running systemd-boot and sddm/Xorg. Note that the i915 driver is within
initrd while the Nvidia one is not.
Without this patch, the splash presented by systemd-boot (UEFI BGRT) is
torn down as the code-path kicks in, leaving the monitor blank until the
login manager starts.
Same issue were reported with plymouth/grub, although personally I
wasn't able to get them to behave on my setup.
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
---
Supersedes
https://lore.kernel.org/dri-devel/20210516171432.1734268-1-emil.l.velikov@gmail.com/
Ville, others,
Patch is based against drm-intel/drm-intel-next and will apply cleanly
against drm-intel/drm-intel-fixes.
If possible, can one of the i915 maintainers apply it to the latter?
Thanks
Emil
---
drivers/gpu/drm/i915/display/intel_vga.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_vga.c b/drivers/gpu/drm/i915/display/intel_vga.c
index be333699c515..7beef1206097 100644
--- a/drivers/gpu/drm/i915/display/intel_vga.c
+++ b/drivers/gpu/drm/i915/display/intel_vga.c
@@ -29,6 +29,9 @@ void intel_vga_disable(struct drm_i915_private *dev_priv)
i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv);
u8 sr1;
+ if (intel_de_read(dev_priv, vga_reg) & VGA_DISP_DISABLE)
+ return;
+
/* WaEnableVGAAccessThroughIOPort:ctg,elk,ilk,snb,ivb,vlv,hsw */
vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
outb(SR01, VGA_SR_INDEX);
--
2.31.1
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next reply other threads:[~2021-06-04 15:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-04 15:49 Emil Velikov [this message]
2021-06-04 16:57 ` [Intel-gfx] ✓ Fi.CI.BAT: success for drm/i915: apply WaEnableVGAAccessThroughIOPort as needed Patchwork
2021-06-04 18:12 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
2021-06-09 9:18 ` [Intel-gfx] [PATCH] " Emil Velikov
2021-06-10 15:01 ` Ville Syrjälä
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