Hi Zack Am 30.01.24 um 20:38 schrieb Zack Rusin:
On Fri, Jan 12, 2024 at 4:20 PM Ian Forbes <ian.forbes@xxxxxxxxxxxx> wrote:SVGA requires surfaces to fit within graphics memory (max_mob_pages) which means that modes with a final buffer size that would exceed graphics memory must be pruned otherwise creation will fail. Additionally, device commands which use multiple graphics resources must have all their resources fit within graphics memory for the duration of the command. Thus we need a small carve out of 1/4 of graphics memory to ensure commands likes surface copies to the primary framebuffer for cursor composition or damage clips can fit within graphics memory. This fixes an issue where VMs with low graphics memory (< 64MiB) configured with high resolution mode boot to a black screen because surface creation fails. Signed-off-by: Ian Forbes <ian.forbes@xxxxxxxxxxxx> --- drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c index 28ff30e32fab..39d6d17fc488 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c @@ -2854,12 +2854,12 @@ enum drm_mode_status vmw_connector_mode_valid(struct drm_connector *connector, struct vmw_private *dev_priv = vmw_priv(dev); u32 max_width = dev_priv->texture_max_width; u32 max_height = dev_priv->texture_max_height; - u32 assumed_cpp = 4; + u32 assumed_cpp = dev_priv->assume_16bpp ? 2 : 4; + u32 pitch = mode->hdisplay * assumed_cpp; + u64 total = mode->vdisplay * pitch; + bool using_stdu = dev_priv->active_display_unit == vmw_du_screen_target; - if (dev_priv->assume_16bpp) - assumed_cpp = 2; - - if (dev_priv->active_display_unit == vmw_du_screen_target) { + if (using_stdu) { max_width = min(dev_priv->stdu_max_width, max_width); max_height = min(dev_priv->stdu_max_height, max_height); } @@ -2870,9 +2870,13 @@ enum drm_mode_status vmw_connector_mode_valid(struct drm_connector *connector, if (max_height < mode->vdisplay) return MODE_BAD_VVALUE; - if (!vmw_kms_validate_mode_vram(dev_priv, - mode->hdisplay * assumed_cpp, - mode->vdisplay)) + if (using_stdu && + (total > (dev_priv->max_mob_pages * PAGE_SIZE * 3 / 4) ||Could you export that computation somewhere where we could document why we're doing this? Just to not leave the awkward "* 3 /4" that everyone reading this code will wonder about?
There's code in VRAM helpers that does a similar test. [1] But the VRAM helpers are obsolete. I guess that TTM could contain such a test somewhere by testing against a max_bo_size for each TTM resource. Whether that is feasible in practice is a different question. Maybe ask the TTM maintainers.
Best regards Thomas[1] https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_gem_vram_helper.c#L1156
And also make sure you indent this correctly, "dim checkpatch" should warn about this. z
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstrasse 146, 90461 Nuernberg, Germany GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman HRB 36809 (AG Nuernberg)
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