releases/4.6.5/drm-vmwgfx-work-around-mode-set-failure-in-2d-vms.patch

   1 From 7c20d213dd3cd6295bf9162730e7a368af957854 Mon Sep 17 00:00:00 2001
   2 From: Sinclair Yeh <syeh@vmware.com>
   3 Date: Wed, 29 Jun 2016 11:29:47 -0700
   4 Subject: drm/vmwgfx: Work around mode set failure in 2D VMs
   5
   6 From: Sinclair Yeh <syeh@vmware.com>
   7
   8 commit 7c20d213dd3cd6295bf9162730e7a368af957854 upstream.
   9
  10 In a low-memory 2D VM, fbdev can take up a large percentage of
  11 available memory, making them unavailable for other DRM clients.
  12
  13 Since we do not take fbdev into account when filtering modes,
  14 we end up claiming to support more modes than we actually do.
  15
  16 As a result, users get a black screen when setting a mode too
  17 large for current available memory.  In a low-memory VM
  18 configuration, users can get a black screen for a mode as low
  19 as 1024x768.
  20
  21 The current mode filtering mechanism keys off of
  22 SVGA_REG_SUGGESTED_GBOBJECT_MEM_SIZE_KB, i.e. the maximum amount
  23 of surface memory we have.  Since this value is a performance
  24 suggestion, not a hard limit, and since there should not be much
  25 of a performance impact for a 2D VM, rather than filtering out
  26 more modes, we will just allow ourselves to exceed the SVGA's
  27 performance suggestion.
  28
  29 Also changed assumed bpp to 32 from 16 to make sure we can
  30 actually support all the modes listed.
  31
  32 Signed-off-by: Sinclair Yeh <syeh@vmware.com>
  33 Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
  34 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  35
  36 ---
  37  drivers/gpu/drm/vmwgfx/vmwgfx_drv.c |    7 +++++++
  38  drivers/gpu/drm/vmwgfx/vmwgfx_kms.c |    9 +--------
  39  2 files changed, 8 insertions(+), 8 deletions(-)
  40
  41 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
  42 +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
  43 @@ -704,6 +704,13 @@ static int vmw_driver_load(struct drm_de
  44                         vmw_read(dev_priv,
  45                                  SVGA_REG_SUGGESTED_GBOBJECT_MEM_SIZE_KB);
  46
  47 +               /*
  48 +                * Workaround for low memory 2D VMs to compensate for the
  49 +                * allocation taken by fbdev
  50 +                */
  51 +               if (!(dev_priv->capabilities & SVGA_CAP_3D))
  52 +                       mem_size *= 2;
  53 +
  54                 dev_priv->max_mob_pages = mem_size * 1024 / PAGE_SIZE;
  55                 dev_priv->prim_bb_mem =
  56                         vmw_read(dev_priv,
  57 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
  58 +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
  59 @@ -1553,14 +1553,7 @@ int vmw_du_connector_fill_modes(struct d
  60                 DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_PVSYNC)
  61         };
  62         int i;
  63 -       u32 assumed_bpp = 2;
  64 -
  65 -       /*
  66 -        * If using screen objects, then assume 32-bpp because that's what the
  67 -        * SVGA device is assuming
  68 -        */
  69 -       if (dev_priv->active_display_unit == vmw_du_screen_object)
  70 -               assumed_bpp = 4;
  71 +       u32 assumed_bpp = 4;
  72
  73         if (dev_priv->assume_16bpp)
  74                 assumed_bpp = 2;