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Current vga arbiter implementation in i915 needs a re-design. The current approach would cause real problems if anyone actually needs to talk another GPU using legacy VGA resources. The main issue is that X becomes a slideshow if it thinks there are multiple GPUs that have VGA decoding enabled as it insists on adjusting the VGA routing pretty much for every little operation involving any of the GPUs. The cleanup will be planned for i915. Meanwhile to focus on Xe upstreaming and have a cleaner separation, the said functionality is being moved to a different file exclusive for i915. Xe driver will re-use rest of the display code from i915. v2: Addressed Jani Nikula's review comments. v3: Dropped a duplicate function (Jani) v4: Updated commit message with reasoning as sugested by Ville. Signed-off-by: Uma Shankar <uma.shankar@intel.com> Reviewed-by: Arun R Murthy <arun.r.murthy@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20230929074306.1533859-1-uma.shankar@intel.com
126 lines
3.5 KiB
C
126 lines
3.5 KiB
C
// SPDX-License-Identifier: MIT
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/*
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* Copyright © 2019 Intel Corporation
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*/
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#include <linux/vgaarb.h>
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#include <video/vga.h>
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#include "soc/intel_gmch.h"
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#include "i915_drv.h"
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#include "i915_reg.h"
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#include "intel_de.h"
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#include "intel_vga.h"
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static i915_reg_t intel_vga_cntrl_reg(struct drm_i915_private *i915)
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{
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if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915))
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return VLV_VGACNTRL;
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else if (DISPLAY_VER(i915) >= 5)
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return CPU_VGACNTRL;
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else
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return VGACNTRL;
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}
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/* Disable the VGA plane that we never use */
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void intel_vga_disable(struct drm_i915_private *dev_priv)
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{
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struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
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i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv);
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u8 sr1;
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if (intel_de_read(dev_priv, vga_reg) & VGA_DISP_DISABLE)
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return;
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/* WaEnableVGAAccessThroughIOPort:ctg,elk,ilk,snb,ivb,vlv,hsw */
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vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
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outb(0x01, VGA_SEQ_I);
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sr1 = inb(VGA_SEQ_D);
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outb(sr1 | VGA_SR01_SCREEN_OFF, VGA_SEQ_D);
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vga_put(pdev, VGA_RSRC_LEGACY_IO);
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udelay(300);
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intel_de_write(dev_priv, vga_reg, VGA_DISP_DISABLE);
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intel_de_posting_read(dev_priv, vga_reg);
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}
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void intel_vga_redisable_power_on(struct drm_i915_private *dev_priv)
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{
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i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv);
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if (!(intel_de_read(dev_priv, vga_reg) & VGA_DISP_DISABLE)) {
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drm_dbg_kms(&dev_priv->drm,
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"Something enabled VGA plane, disabling it\n");
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intel_vga_disable(dev_priv);
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}
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}
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void intel_vga_redisable(struct drm_i915_private *i915)
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{
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intel_wakeref_t wakeref;
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/*
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* This function can be called both from intel_modeset_setup_hw_state or
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* at a very early point in our resume sequence, where the power well
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* structures are not yet restored. Since this function is at a very
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* paranoid "someone might have enabled VGA while we were not looking"
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* level, just check if the power well is enabled instead of trying to
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* follow the "don't touch the power well if we don't need it" policy
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* the rest of the driver uses.
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*/
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wakeref = intel_display_power_get_if_enabled(i915, POWER_DOMAIN_VGA);
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if (!wakeref)
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return;
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intel_vga_redisable_power_on(i915);
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intel_display_power_put(i915, POWER_DOMAIN_VGA, wakeref);
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}
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void intel_vga_reset_io_mem(struct drm_i915_private *i915)
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{
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struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
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/*
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* After we re-enable the power well, if we touch VGA register 0x3d5
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* we'll get unclaimed register interrupts. This stops after we write
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* anything to the VGA MSR register. The vgacon module uses this
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* register all the time, so if we unbind our driver and, as a
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* consequence, bind vgacon, we'll get stuck in an infinite loop at
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* console_unlock(). So make here we touch the VGA MSR register, making
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* sure vgacon can keep working normally without triggering interrupts
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* and error messages.
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*/
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vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
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outb(inb(VGA_MIS_R), VGA_MIS_W);
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vga_put(pdev, VGA_RSRC_LEGACY_IO);
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}
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int intel_vga_register(struct drm_i915_private *i915)
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{
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struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
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int ret;
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/*
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* If we have > 1 VGA cards, then we need to arbitrate access to the
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* common VGA resources.
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*
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* If we are a secondary display controller (!PCI_DISPLAY_CLASS_VGA),
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* then we do not take part in VGA arbitration and the
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* vga_client_register() fails with -ENODEV.
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*/
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ret = vga_client_register(pdev, intel_gmch_vga_set_decode);
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if (ret && ret != -ENODEV)
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return ret;
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return 0;
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}
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void intel_vga_unregister(struct drm_i915_private *i915)
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{
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struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
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vga_client_unregister(pdev);
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}
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