mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-24 01:41:39 +00:00
drm/i915: Only apply a rmw mmio update if the value changes
If we try to clear, or even set, a bit in the register that doesn't change the register state; skip the write. There's a slight danger in that the register acts as a latch-on-write, but I do not think we use a rmw cycle with any such latch registers. Suggested-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190917080029.27632-1-chris@chris-wilson.co.uk
This commit is contained in:
parent
bb120e1171
commit
80fa64d620
1 changed files with 10 additions and 10 deletions
|
@ -378,23 +378,23 @@ intel_uncore_read64_2x32(struct intel_uncore *uncore,
|
|||
static inline void intel_uncore_rmw(struct intel_uncore *uncore,
|
||||
i915_reg_t reg, u32 clear, u32 set)
|
||||
{
|
||||
u32 val;
|
||||
u32 old, val;
|
||||
|
||||
val = intel_uncore_read(uncore, reg);
|
||||
val &= ~clear;
|
||||
val |= set;
|
||||
intel_uncore_write(uncore, reg, val);
|
||||
old = intel_uncore_read(uncore, reg);
|
||||
val = (old & ~clear) | set;
|
||||
if (val != old)
|
||||
intel_uncore_write(uncore, reg, val);
|
||||
}
|
||||
|
||||
static inline void intel_uncore_rmw_fw(struct intel_uncore *uncore,
|
||||
i915_reg_t reg, u32 clear, u32 set)
|
||||
{
|
||||
u32 val;
|
||||
u32 old, val;
|
||||
|
||||
val = intel_uncore_read_fw(uncore, reg);
|
||||
val &= ~clear;
|
||||
val |= set;
|
||||
intel_uncore_write_fw(uncore, reg, val);
|
||||
old = intel_uncore_read_fw(uncore, reg);
|
||||
val = (old & ~clear) | set;
|
||||
if (val != old)
|
||||
intel_uncore_write_fw(uncore, reg, val);
|
||||
}
|
||||
|
||||
static inline int intel_uncore_write_and_verify(struct intel_uncore *uncore,
|
||||
|
|
Loading…
Reference in a new issue