@@ -1273,10 +1273,12 @@ int i915_reg_read_ioctl(struct drm_device *dev,
struct drm_i915_private *dev_priv = dev->dev_private;
struct drm_i915_reg_read *reg = data;
struct register_whitelist const *entry = whitelist;
+ unsigned size;
+ u64 offset;
int i, ret = 0;
for (i = 0; i < ARRAY_SIZE(whitelist); i++, entry++) {
- if (entry->offset == reg->offset &&
+ if (entry->offset == (reg->offset & -entry->size) &&
(1 << INTEL_INFO(dev)->gen & entry->gen_bitmask))
break;
}
@@ -1284,23 +1286,33 @@ int i915_reg_read_ioctl(struct drm_device *dev,
if (i == ARRAY_SIZE(whitelist))
return -EINVAL;
+ /* We use the low bits to encode extra flags as the register should
+ * be naturally aligned (and those that are not so aligned merely
+ * limit the available flags for that register).
+ */
+ offset = entry->offset;
+ size = entry->size;
+ size |= reg->offset ^ offset;
+
intel_runtime_pm_get(dev_priv);
- switch (entry->size) {
+ switch (size) {
+ case 8 | 1:
+ reg->val = I915_READ64_2x32(offset, offset+4);
+ break;
case 8:
- reg->val = I915_READ64(reg->offset);
+ reg->val = I915_READ64(offset);
break;
case 4:
- reg->val = I915_READ(reg->offset);
+ reg->val = I915_READ(offset);
break;
case 2:
- reg->val = I915_READ16(reg->offset);
+ reg->val = I915_READ16(offset);
break;
case 1:
- reg->val = I915_READ8(reg->offset);
+ reg->val = I915_READ8(offset);
break;
default:
- WARN_ON(1);
ret = -EINVAL;
goto out;
}
@@ -1042,6 +1042,14 @@ struct drm_i915_reg_read {
__u64 offset;
__u64 val; /* Return value */
};
+/* Known registers:
+ *
+ * Render engine timestamp - 0x2358 + 64bit - gen7+
+ * - Note this register returns an invalid value if using the default
+ * single instruction 8byte read, in order to workaround that use
+ * offset (0x2538 | 1) instead.
+ *
+ */
struct drm_i915_reset_stats {
__u32 ctx_id;
This is a note to let you know that I have just added a patch titled drm/i915: Use two 32bit reads for select 64bit REG_READ ioctls to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue This patch is scheduled to be released in version 3.19.8-ckt6. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.19.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 873c099f0f2ecae5858aa52fbfc0a60fb4959cbd Mon Sep 17 00:00:00 2001 From: Chris Wilson <chris@chris-wilson.co.uk> Date: Thu, 16 Jul 2015 12:37:56 +0100 Subject: drm/i915: Use two 32bit reads for select 64bit REG_READ ioctls MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 648a9bc5308d952f2c80772301b339f73026f013 upstream. Since the hardware sometimes mysteriously totally flummoxes the 64bit read of a 64bit register when read using a single instruction, split the read into two instructions. Since the read here is of automatically incrementing timestamp counters, we also have to be very careful in order to make sure that it does not increment between the two instructions. However, since userspace tried to workaround this issue and so enshrined this ABI for a broken hardware read and in the process neglected that the read only fails in some environments, we have to introduce a new uABI flag for userspace to request the 2x32 bit accurate read of the timestamp. v2: Fix alignment check and include details of the workaround for userspace. Reported-by: Karol Herbst <freedesktop@karolherbst.de> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91317 Testcase: igt/gem_reg_read Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Michał Winiarski <michal.winiarski@intel.com> Tested-by: Michał Winiarski <michal.winiarski@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> [ kamal: backport to 3.19-stable: context ] Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/gpu/drm/i915/intel_uncore.c | 26 +++++++++++++++++++------- include/uapi/drm/i915_drm.h | 8 ++++++++ 2 files changed, 27 insertions(+), 7 deletions(-) -- 1.9.1