Re: [Intel-gfx] [PATCH] drm/i915: fix device info for devices without display

[Lucas De Marchi <lucas.demarchi@intel.com>]

On Mon, Sep 19, 2022 at 11:10:53AM +0300, Jani Nikula wrote:
>On Fri, 16 Sep 2022, Lucas De Marchi <lucas.demarchi@intel.com> wrote:
>> On Fri, Sep 16, 2022 at 11:26:42AM +0300, Jani Nikula wrote:
>>>Commit 00c6cbfd4e8a ("drm/i915: move pipe_mask and cpu_transcoder_mask
>>>to runtime info") moved the pipe_mask member from struct
>>>intel_device_info to intel_runtime_info, but overlooked some of our
>>>platforms initializing device info .display = {}. This is significant,
>>>as pipe_mask is the single point of truth for a device having a display
>>>or not; the platforms in question left pipe_mask to whatever was set for
>>>the platforms they "inherit" from in the complex macro scheme we have.
>>>
>>>Add new NO_DISPLAY macro initializing .__runtime.pipe_mask = 0, which
>>>will cause the device info .display sub-struct to be zeroed in
>>>intel_device_info_runtime_init(). A better solution (or simply audit of
>>>proper use of HAS_DISPLAY() checks) is required before moving forward
>>>with [1].
>>>
>>>Also clear all the display related members in runtime info if there's no
>>>display. The latter is a bit tedious, but it's for completeness at this
>>>time, to ensure similar functionality as before.
>>>
>>>[1] https://lore.kernel.org/r/dfda1bf67f02ceb07c280b7a13216405fd1f7a34.1660137416.git.jani.nikula@intel.com
>>>
>>>Fixes: 00c6cbfd4e8a ("drm/i915: move pipe_mask and cpu_transcoder_mask to runtime info")
>>>Cc: Lucas De Marchi <lucas.demarchi@intel.com>
>>>Cc: Maarten Lankhort <maarten.lankhorst@linux.intel.com>
>>>Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>>>---
>>> drivers/gpu/drm/i915/i915_pci.c          | 11 ++++++-----
>>> drivers/gpu/drm/i915/intel_device_info.c |  6 ++++++
>>> 2 files changed, 12 insertions(+), 5 deletions(-)
>>>
>>>diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
>>>index 77e7df21f539..cd4487a1d3be 100644
>>>--- a/drivers/gpu/drm/i915/i915_pci.c
>>>+++ b/drivers/gpu/drm/i915/i915_pci.c
>>>@@ -41,6 +41,8 @@
>>> 	.__runtime.media.ip.ver = (x), \
>>> 	.__runtime.display.ip.ver = (x)
>>>
>>>+#define NO_DISPLAY .__runtime.pipe_mask = 0
>>>+
>>> #define I845_PIPE_OFFSETS \
>>> 	.display.pipe_offsets = { \
>>> 		[TRANSCODER_A] = PIPE_A_OFFSET,	\
>>>@@ -519,9 +521,8 @@ static const struct intel_device_info ivb_m_gt2_info = {
>>> static const struct intel_device_info ivb_q_info = {
>>> 	GEN7_FEATURES,
>>> 	PLATFORM(INTEL_IVYBRIDGE),
>>>+	NO_DISPLAY,
>>> 	.gt = 2,
>>>-	.__runtime.pipe_mask = 0, /* legal, last one wins */
>>>-	.__runtime.cpu_transcoder_mask = 0,
>>> 	.has_l3_dpf = 1,
>>> };
>>>
>>>@@ -1039,7 +1040,7 @@ static const struct intel_device_info xehpsdv_info = {
>>> 	XE_HPM_FEATURES,
>>> 	DGFX_FEATURES,
>>> 	PLATFORM(INTEL_XEHPSDV),
>>>-	.display = { },
>>>+	NO_DISPLAY,
>>> 	.has_64k_pages = 1,
>>> 	.needs_compact_pt = 1,
>>> 	.has_media_ratio_mode = 1,
>>>@@ -1081,7 +1082,7 @@ static const struct intel_device_info dg2_info = {
>>>
>>> static const struct intel_device_info ats_m_info = {
>>> 	DG2_FEATURES,
>>>-	.display = { 0 },
>>>+	NO_DISPLAY,
>>> 	.require_force_probe = 1,
>>> 	.tuning_thread_rr_after_dep = 1,
>>> };
>>>@@ -1103,7 +1104,7 @@ static const struct intel_device_info pvc_info = {
>>> 	.__runtime.graphics.ip.rel = 60,
>>> 	.__runtime.media.ip.rel = 60,
>>> 	PLATFORM(INTEL_PONTEVECCHIO),
>>>-	.display = { 0 },
>>>+	NO_DISPLAY,
>>> 	.has_flat_ccs = 0,
>>> 	.__runtime.platform_engine_mask =
>>> 		BIT(BCS0) |
>>>diff --git a/drivers/gpu/drm/i915/intel_device_info.c b/drivers/gpu/drm/i915/intel_device_info.c
>>>index 1434dc33cf49..20575eb77ea7 100644
>>>--- a/drivers/gpu/drm/i915/intel_device_info.c
>>>+++ b/drivers/gpu/drm/i915/intel_device_info.c
>>>@@ -433,8 +433,14 @@ void intel_device_info_runtime_init(struct drm_i915_private *dev_priv)
>>> 		dev_priv->drm.driver_features &= ~(DRIVER_MODESET |
>>> 						   DRIVER_ATOMIC);
>>> 		memset(&info->display, 0, sizeof(info->display));
>>>+
>>>+		runtime->cpu_transcoder_mask = 0;
>>> 		memset(runtime->num_sprites, 0, sizeof(runtime->num_sprites));
>>> 		memset(runtime->num_scalers, 0, sizeof(runtime->num_scalers));
>>>+		runtime->fbc_mask = 0;
>>>+		runtime->has_hdcp = false;
>>>+		runtime->has_dmc = false;
>>>+		runtime->has_dsc = false;
>>
>> why are these not inside __runtime.display?
>
>The short answer, because there isn't one. It's an anonymous struct for
>now.

/me confused... that doesn't really answer the question. Why would we
not move these inside a display substruct? When moving stuff out of
device_info.display.x, it seems the better place would be inside
__runtime.display.x, not __runtime.x.

I must be missing something here. We had a "recent" move of these flags
lying around in device_info to be inside a display substruct -
commit d53db442db36 ("drm/i915: Move display device info capabilities to its
own struct") - to be able to keep the display flags together
and zero them together.

Lucas De Marchi

>
>BR,
>Jani.
>
>
>-- 
>Jani Nikula, Intel Open Source Graphics Center