This patchset addresses a couple of issues with the i915 gmbus implementation: * fixes misassigned pin port pair for HDMI-D * fixes write transactions when they are the only transaction requested (including large >4-byte writes) * returns -ENXIO and -ETIMEDOUT as appropriate so upper layers can handled i2c transaction failures * optimizes the typical read transaction case by using the INDEX cycle
The patchset should apply cleanly onto linus/master. It is inspired by, but completely supercedes, a similar patch submitted recently by Benson Leung (bleung@chromium.org). I'd be happy to rebase on a different tree if necessary.
Note: There is one more patch in the set which I have not included here. It enables the PCH GMBUS interrupt and makes use of it to eliminate the very slow 'wait_for' polling loop. This patch was not included, however, because there is at least one case I have discovered where the i915 driver issues a GMBUS transaction AFTER its interrupts have been initialized, but BEFORE it they have been enabled. Both the gmbus transaction and irq initialization occur during i915_load_modeset_init(), but the gmbus transaction happens first, during: intel_modeset_init() intel_setup_outputs() intel_lvds_init() drm_get_edid() Is there a way to switch the order of these to events? Or does it make more sense for the gmbus driver to check a "bool irq_enabled", and choose whether to poll or use the GMBUS interrupt? ... or both?
Daniel Kurtz (9): drm/i915/intel_i2c: cleanup drm/i915/intel_i2c: assign HDMI port D to pin pair 6 drm/i915/intel_i2c: refactor using intel_gmbus_get_bus drm/i915/intel_i2c: cleanup gmbus/gpio pin assignments drm/i915/intel_i2c: add locking around i2c algorithm accesses drm/i915/intel_i2c: return -ENXIO for device NAK drm/i915/intel_i2c: use WAIT cycle, not STOP drm/i915/intel_i2c: use INDEX cycles for i2c read transactions drm/i915/intel_i2c: reuse GMBUS2 value read in polling loop
drivers/gpu/drm/i915/i915_drv.h | 5 +- drivers/gpu/drm/i915/i915_reg.h | 5 +- drivers/gpu/drm/i915/intel_bios.c | 10 ++- drivers/gpu/drm/i915/intel_crt.c | 13 ++-- drivers/gpu/drm/i915/intel_drv.h | 3 +- drivers/gpu/drm/i915/intel_dvo.c | 4 +- drivers/gpu/drm/i915/intel_hdmi.c | 29 +++--- drivers/gpu/drm/i915/intel_i2c.c | 175 +++++++++++++++++++++++++----------- drivers/gpu/drm/i915/intel_lvds.c | 2 +- drivers/gpu/drm/i915/intel_modes.c | 6 +- drivers/gpu/drm/i915/intel_sdvo.c | 10 +-- 11 files changed, 165 insertions(+), 97 deletions(-)