Hi Chris, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on drm-intel/for-linux-next] [also build test WARNING on drm-tip/drm-tip next-20200717] [cannot apply to linus/master v5.8-rc5] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Chris-Wilson/drm-i915-Remove-req... base: git://anongit.freedesktop.org/drm-intel for-linux-next config: i386-allyesconfig (attached as .config) compiler: gcc-9 (Debian 9.3.0-14) 9.3.0 reproduce (this is a W=1 build): # save the attached .config to linux build tree make W=1 ARCH=i386 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): 71 | void intel_breadcrumbs_park(struct intel_breadcrumbs *b) | ^~~~~~~~~~~~~~~~~~~~~~ 248 | intel_breadcrumbs_create(struct intel_engine_cs *irq_engine) | ^~~~~~~~~~~~~~~~~~~~~~~~ 269 | void intel_breadcrumbs_reset(struct intel_breadcrumbs *b) | ^~~~~~~~~~~~~~~~~~~~~~~ 286 | void intel_breadcrumbs_free(struct intel_breadcrumbs *b) | ^~~~~~~~~~~~~~~~~~~~~~ 344 | bool i915_request_enable_breadcrumb(struct i915_request *rq) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 400 | void i915_request_cancel_breadcrumb(struct i915_request *rq) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 423 | void intel_engine_print_breadcrumbs(struct intel_engine_cs *engine, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ vim +/intel_breadcrumbs_park +71 drivers/gpu/drm/i915/gt/intel_breadcrumbs.c 70 72 { 73 unsigned long flags; 74 75 if (!READ_ONCE(b->irq_armed)) 76 return; 77 78 spin_lock_irqsave(&b->irq_lock, flags); 79 if (b->irq_armed) 80 __intel_breadcrumbs_disarm_irq(b); 81 spin_unlock_irqrestore(&b->irq_lock, flags); 82 } 83 84 static inline bool __request_completed(const struct i915_request *rq) 85 { 86 return i915_seqno_passed(__hwsp_seqno(rq), rq->fence.seqno); 87 } 88 89 __maybe_unused static bool 90 check_signal_order(struct intel_context *ce, struct i915_request *rq) 91 { 92 if (!list_is_last(&rq->signal_link, &ce->signals) && 93 i915_seqno_passed(rq->fence.seqno, 94 list_next_entry(rq, signal_link)->fence.seqno)) 95 return false; 96 97 if (!list_is_first(&rq->signal_link, &ce->signals) && 98 i915_seqno_passed(list_prev_entry(rq, signal_link)->fence.seqno, 99 rq->fence.seqno)) 100 return false; 101 102 return true; 103 } 104 105 static bool 106 __dma_fence_signal(struct dma_fence *fence) 107 { 108 return !test_and_set_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags); 109 } 110 111 static void 112 __dma_fence_signal__timestamp(struct dma_fence *fence, ktime_t timestamp) 113 { 114 fence->timestamp = timestamp; 115 set_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags); 116 trace_dma_fence_signaled(fence); 117 } 118 119 static void 120 __dma_fence_signal__notify(struct dma_fence *fence, 121 const struct list_head *list) 122 { 123 struct dma_fence_cb *cur, *tmp; 124 125 lockdep_assert_held(fence->lock); 126 127 list_for_each_entry_safe(cur, tmp, list, node) { 128 INIT_LIST_HEAD(&cur->node); 129 cur->func(fence, cur); 130 } 131 } 132 133 static void add_retire(struct intel_breadcrumbs *b, struct intel_timeline *tl) 134 { 135 if (b->irq_engine) 136 intel_engine_add_retire(b->irq_engine, tl); 137 } 138 139 static void __signal_request(struct i915_request *rq, struct list_head *signals) 140 { 141 clear_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags); 142 143 if (!__dma_fence_signal(&rq->fence)) 144 return; 145 146 i915_request_get(rq); 147 list_add_tail(&rq->signal_link, signals); 148 } 149 150 static void signal_irq_work(struct irq_work *work) 151 { 152 struct intel_breadcrumbs *b = container_of(work, typeof(*b), irq_work); 153 const ktime_t timestamp = ktime_get(); 154 struct intel_context *ce, *cn; 155 struct list_head *pos, *next; 156 LIST_HEAD(signal); 157 158 spin_lock(&b->irq_lock); 159 160 if (b->irq_armed && list_empty(&b->signalers)) 161 __intel_breadcrumbs_disarm_irq(b); 162 163 list_splice_init(&b->signaled_requests, &signal); 164 165 list_for_each_entry_safe(ce, cn, &b->signalers, signal_link) { 166 GEM_BUG_ON(list_empty(&ce->signals)); 167 168 list_for_each_safe(pos, next, &ce->signals) { 169 struct i915_request *rq = 170 list_entry(pos, typeof(*rq), signal_link); 171 172 GEM_BUG_ON(!check_signal_order(ce, rq)); 173 if (!__request_completed(rq)) 174 break; 175 176 /* 177 * Queue for execution after dropping the signaling 178 * spinlock as the callback chain may end up adding 179 * more signalers to the same context or engine. 180 */ 181 __signal_request(rq, &signal); 182 } 183 184 /* 185 * We process the list deletion in bulk, only using a list_add 186 * (not list_move) above but keeping the status of 187 * rq->signal_link known with the I915_FENCE_FLAG_SIGNAL bit. 188 */ 189 if (!list_is_first(pos, &ce->signals)) { 190 /* Advance the list to the first incomplete request */ 191 __list_del_many(&ce->signals, pos); 192 if (&ce->signals == pos) { /* now empty */ 193 list_del_init(&ce->signal_link); 194 add_retire(b, ce->timeline); 195 } 196 } 197 } 198 199 spin_unlock(&b->irq_lock); 200 201 list_for_each_safe(pos, next, &signal) { 202 struct i915_request *rq = 203 list_entry(pos, typeof(*rq), signal_link); 204 struct list_head cb_list; 205 206 spin_lock(&rq->lock); 207 list_replace(&rq->fence.cb_list, &cb_list); 208 __dma_fence_signal__timestamp(&rq->fence, timestamp); 209 __dma_fence_signal__notify(&rq->fence, &cb_list); 210 spin_unlock(&rq->lock); 211 212 i915_request_put(rq); 213 } 214 } 215 216 static void __intel_breadcrumbs_arm_irq(struct intel_breadcrumbs *b) 217 { 218 lockdep_assert_held(&b->irq_lock); 219 220 if (b->irq_armed) 221 return; 222 223 GEM_BUG_ON(!b->irq_engine); 224 if (!intel_gt_pm_get_if_awake(b->irq_engine->gt)) 225 return; 226 227 /* 228 * The breadcrumb irq will be disarmed on the interrupt after the 229 * waiters are signaled. This gives us a single interrupt window in 230 * which we can add a new waiter and avoid the cost of re-enabling 231 * the irq. 232 */ 233 WRITE_ONCE(b->irq_armed, true); 234 235 /* 236 * Since we are waiting on a request, the GPU should be busy 237 * and should have its own rpm reference. This is tracked 238 * by i915->gt.awake, we can forgo holding our own wakref 239 * for the interrupt as before i915->gt.awake is released (when 240 * the driver is idle) we disarm the breadcrumbs. 241 */ 242 243 if (!b->irq_enabled++) 244 irq_enable(b->irq_engine); 245 } 246 247 struct intel_breadcrumbs * 249 { 250 struct intel_breadcrumbs *b; 251 252 b = kzalloc(sizeof(*b), GFP_KERNEL); 253 if (!b) 254 return NULL; 255 256 spin_lock_init(&b->irq_lock); 257 INIT_LIST_HEAD(&b->signalers); 258 INIT_LIST_HEAD(&b->signaled_requests); 259 260 init_irq_work(&b->irq_work, signal_irq_work); 261 262 b->irq_engine = irq_engine; 263 if (!irq_engine) 264 b->irq_armed = true; /* fake HW, used for irq_work */ 265 266 return b; 267 } 268 270 { 271 unsigned long flags; 272 273 if (!b->irq_engine) 274 return; 275 276 spin_lock_irqsave(&b->irq_lock, flags); 277 278 if (b->irq_enabled) 279 irq_enable(b->irq_engine); 280 else 281 irq_disable(b->irq_engine); 282 283 spin_unlock_irqrestore(&b->irq_lock, flags); 284 } 285 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org