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drm/i915/aux: use polling when irqs are unavailable

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PTL with physically disconnected display was observed to have 40s longer
execution time when testing xe_fault_injection@xe_guc_mmio_send_recv.
The issue has not been seen when reverting commit 40a9f77a28 ("Revert
"drm/i915/dp: change aux_ctl reg read to polling read"").

Apparently the configuration suffers from not having AUX enabled when
using interrupts. One probable cause can be xe enabling interrupts too
late: interrupts need memory allocations which currently can't be done
before the display FB takeover is done.

As for now, use polling for AUX in case interrupts are unavailable.

Fixes: 40a9f77a28 ("Revert "drm/i915/dp: change aux_ctl reg read to polling read"")
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Michał Grzelak <michal.grzelak@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260416163744.288107-1-michal.grzelak@intel.com
(cherry picked from commit 05e0550b65cd1604bd515fbc65f522bce4c10a87)
Signed-off-by: Tvrtko Ursulin <tursulin@ursulin.net>
This commit is contained in:
Michał Grzelak 2026-04-16 18:37:44 +02:00 committed by Tvrtko Ursulin
parent 5c4063c87a
commit 202e77cf2e
1 changed files with 16 additions and 4 deletions
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20
drivers/gpu/drm/i915/display/intel_dp_aux.c
View File

@ -12,6 +12,7 @@
#include "intel_dp.h"
#include "intel_dp_aux.h"
#include "intel_dp_aux_regs.h"
#include "intel_parent.h"
#include "intel_pps.h"
#include "intel_quirks.h"
#include "intel_tc.h"
@ -60,18 +61,29 @@ intel_dp_aux_wait_done(struct intel_dp *intel_dp)
struct intel_display *display = to_intel_display(intel_dp);
i915_reg_t ch_ctl = intel_dp->aux_ch_ctl_reg(intel_dp);
const unsigned int timeout_ms = 10;
bool done = true;
u32 status;
bool done;
int ret;
if (intel_parent_irq_enabled(display)) {
#define C (((status = intel_de_read_notrace(display, ch_ctl)) & DP_AUX_CH_CTL_SEND_BUSY) == 0)
done = wait_event_timeout(display->gmbus.wait_queue, C,
msecs_to_jiffies_timeout(timeout_ms));
done = wait_event_timeout(display->gmbus.wait_queue, C,
msecs_to_jiffies_timeout(timeout_ms));
#undef C
} else {
ret = intel_de_wait_ms(display, ch_ctl,
DP_AUX_CH_CTL_SEND_BUSY, 0,
timeout_ms, &status);
if (ret == -ETIMEDOUT)
done = false;
}
if (!done)
drm_err(display->drm,
"%s: did not complete or timeout within %ums (status 0x%08x)\n",
intel_dp->aux.name, timeout_ms, status);
#undef C
return status;
}