[PATCH 1/2] drm/i915/gvt: Set initial PORT_CLK_SEL vreg for BDW

[Zhenyu Wang]

On 2017.06.20 11:37:22 +0800, Xiong Zhang wrote:
> On BDW, when host physical screen and guest virtual screen aren't on
> the same DDI port, guest i915 driver prints the following error and
> stop running.
> [    6.775873] BUG: unable to handle kernel NULL pointer dereference
> at 0000000000000068
> [    6.775928] IP: intel_ddi_clock_get+0x81/0x430 [i915]
> [    6.776206] Call Trace:
> [    6.776233]  ? vgpu_read32+0x4f/0x100 [i915]
> [    6.776264]  intel_ddi_get_config+0x11c/0x230 [i915]
> [    6.776298]  intel_modeset_setup_hw_state+0x313/0xd40 [i915]
> [    6.776334]  intel_modeset_init+0xe49/0x18d0 [i915]
> [    6.776368]  ? vgpu_write32+0x53/0x100 [i915]
> [    6.776731]  ? intel_i2c_reset+0x42/0x50 [i915]
> [    6.777085]  ? intel_setup_gmbus+0x32a/0x350 [i915]
> [    6.777427]  i915_driver_load+0xabc/0x14d0 [i915]
> [    6.777768]  i915_pci_probe+0x4f/0x70 [i915]
> 
> The null pointer is guest intel_crtc_state->shared_dpll which is
> setted in haswell_get_ddi_pll(). When guest and host screen are
> on different DDI port, host driver won't set PORT_CLK_SET(guest_port),
> so haswell_get_ddi_pll() will return null and don't set
> pipe_config->shared_dpll, once the following program refernce this
> structure, it will print the above error.
> 
> This patch set the initial val of guest PORT_CLK_SEL(guest_port) to
> LCPLL_810. And guest i915 driver will reset this value according to
> guest screen mode.
> 

pushed, thanks!

-- 
Open Source Technology Center, Intel ltd.

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