From f0c860246472248a534656d6cdbed5a36d1feb2e Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 23 Mar 2011 17:53:28 +0000 Subject: [PATCH] Revert "drm/i915: Don't save/restore hardware status page address register" This reverts commit a7a75c8f70d6f6a2f16c9f627f938bbee2d32718. There are two different variations on how Intel hardware addresses the "Hardware Status Page". One as a location in physical memory and the other as an offset into the virtual memory of the GPU, used in more recent chipsets. (The HWS itself is a cacheable region of memory which the GPU can write to without requiring CPU synchronisation, used for updating various details of hardware state, such as the position of the GPU head in the ringbuffer, the last breadcrumb seqno, etc). These two types of addresses were updated in different locations of code - one inline with the ringbuffer initialisation, and the other during device initialisation. (The HWS page is logically associated with the rings, and there is one HWS page per ring.) During resume, only the ringbuffers were being re-initialised along with the virtual HWS page, leaving the older physical address HWS untouched. This then caused a hang on the older gen3/4 (915GM, 945GM, 965GM) the first time we tried to synchronise the GPU as the breadcrumbs were never being updated. Reported-and-tested-by: Linus Torvalds Reported-by: Jan Niehusmann Reported-and-tested-by: Justin P. Mattock Reported-and-tested-by: Michael "brot" Groh Cc: Zhenyu Wang Signed-off-by: Chris Wilson Acked-by: Zhenyu Wang --- drivers/gpu/drm/i915/i915_drv.h | 1 + drivers/gpu/drm/i915/i915_suspend.c | 6 ++++++ 2 files changed, 7 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 449650545bb4..5004724ea57e 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -383,6 +383,7 @@ typedef struct drm_i915_private { u32 saveDSPACNTR; u32 saveDSPBCNTR; u32 saveDSPARB; + u32 saveHWS; u32 savePIPEACONF; u32 savePIPEBCONF; u32 savePIPEASRC; diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c index 7e992a8e9098..da474153a0a2 100644 --- a/drivers/gpu/drm/i915/i915_suspend.c +++ b/drivers/gpu/drm/i915/i915_suspend.c @@ -796,6 +796,9 @@ int i915_save_state(struct drm_device *dev) pci_read_config_byte(dev->pdev, LBB, &dev_priv->saveLBB); + /* Hardware status page */ + dev_priv->saveHWS = I915_READ(HWS_PGA); + i915_save_display(dev); /* Interrupt state */ @@ -842,6 +845,9 @@ int i915_restore_state(struct drm_device *dev) pci_write_config_byte(dev->pdev, LBB, dev_priv->saveLBB); + /* Hardware status page */ + I915_WRITE(HWS_PGA, dev_priv->saveHWS); + i915_restore_display(dev); /* Interrupt state */ -- GitLab