On Thu, Jul 03, 2025 at 03:00:19PM +0530, Nautiyal, Ankit K wrote:
On 7/3/2025 3:19 AM, Ville Syrjälä wrote:
On Thu, Jul 03, 2025 at 12:29:37AM +0300, Ville Syrjälä wrote:
On Wed, Jul 02, 2025 at 03:25:21PM -0500, Lucas De Marchi wrote:
On Wed, Jul 02, 2025 at 10:40:34PM +0300, Ville Syrjälä wrote:
On Wed, Jul 02, 2025 at 02:16:18PM +0530, Ankit Nautiyal wrote:
Introduce a generic helper to check display workarounds using an enum.
Convert Wa_16023588340 to use the new interface, simplifying WA checks
and making future additions easier.
v2: Use drm_WARN instead of MISSING_CASE and simplify intel_display_wa
macro. (Jani)
Suggested-by: Jani Nikula <jani.nik...@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nauti...@intel.com>
---
drivers/gpu/drm/i915/display/intel_display_wa.c | 15 +++++++++++++++
drivers/gpu/drm/i915/display/intel_display_wa.h | 9 +++++++++
drivers/gpu/drm/i915/display/intel_fbc.c | 2 +-
3 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display_wa.c
b/drivers/gpu/drm/i915/display/intel_display_wa.c
index f57280e9d041..f5e8d58d9a68 100644
--- a/drivers/gpu/drm/i915/display/intel_display_wa.c
+++ b/drivers/gpu/drm/i915/display/intel_display_wa.c
@@ -3,6 +3,8 @@
* Copyright © 2023 Intel Corporation
*/
+#include "drm/drm_print.h"
+
#include "i915_reg.h"
#include "intel_de.h"
#include "intel_display_core.h"
@@ -39,3 +41,16 @@ void intel_display_wa_apply(struct intel_display *display)
else if (DISPLAY_VER(display) == 11)
gen11_display_wa_apply(display);
}
+
+bool __intel_display_wa(struct intel_display *display, enum intel_display_wa
wa)
+{
+ switch (wa) {
+ case INTEL_DISPLAY_WA_16023588340:
+ return intel_display_needs_wa_16023588340(display);
+ default:
+ drm_WARN(display->drm, 1, "Missing Wa number: %d\n", wa);
+ break;
+ }
+
+ return false;
+}
diff --git a/drivers/gpu/drm/i915/display/intel_display_wa.h
b/drivers/gpu/drm/i915/display/intel_display_wa.h
index babd9d16603d..146ee70d66f7 100644
--- a/drivers/gpu/drm/i915/display/intel_display_wa.h
+++ b/drivers/gpu/drm/i915/display/intel_display_wa.h
@@ -21,4 +21,13 @@ static inline bool intel_display_needs_wa_16023588340(struct
intel_display *disp
bool intel_display_needs_wa_16023588340(struct intel_display *display);
#endif
+enum intel_display_wa {
+ INTEL_DISPLAY_WA_16023588340,
How is anyone supposed to keep track of these random numbers
and what they mean?
they mean there's a h/w workaround that requires that and this is the id
if you need to find more details about it or what platforms/IPs use
that.
I don't want to go look up all the details in the common case.
I just want to read the code and see that it generally makes
sense without having to trawl through the spec/hsd for an
hour every time.
The only time I want to see these numbers is if I really have to
open the spec/hsd for it to double check some details. Othwerwise
it just seems like pointless noise that makes it harder to follow
the code/figure out what the heck is going on.
what is the alternative? The current status quo checking by platform
and/or IP version, dissociated from the WA numbers?
I find it easiest if everything is in one place. I think every
w/a generally should have these:
- which hardware is affected
- what other runtime conditions are required to hit the issue
- what is being done to avoid the issue
- a short human readable explanation of the issue
- the w/a number for looking up futher details
Splitting it all up into random bits and pieces just means more
jumping around all the time, which I find annoying at best.
I suppose one could argue for a more formal thing for these three:
- which hardware is affected
- a short human readable explanation of the issue
- the w/a number for looking up futher details
Whether adding comments with platform and relevant information about
Wa would be sufficient?
Something like:
/*
* Wa_16025573575: PTL/WCL
See the nightmare the intel_workarounds.c became. The comments also
don't match what the code is doing which means it's not only noise, it's
wrong information over time.
* Fix issue with bitbashing on PTL.
* Set masks bits in GPIO CTL and preserve it during bitbashing sequence.
This description not always can be there. So out of the 3 pieces of
information we already have 2.
*/
static bool intel_display_needs_wa_16025573575(struct intel_display
*display)
{
return DISPLAY_VER(display) == 30;
}
Or we want to have some wa_struct with fields for platforms and stuff?
on the xe side we check it once during init and set a bitmap to be used
later. This also allows us to check "what W/A is enabled" from outside
and double check the list of the workarounds for a platform.
Lucas De Marchi
Regards,
Ankit
Might be still a real pain to deal with that due to having to jump
around, but at least it could be used to force people to document
each w/a a bit better.
Basically anything that avoids having to wait for the spec/hsd to
load is a good thing in my book.
There's also the question of what to do with duplicates, as in often
it seems the same issue is present on multiple platforms under different
w/a numbers.
