display: reduce graphics memory impact

The purpose of this patch is to reduce graphics memory usage.
It reduces the size of memory allocated for hashtables from 8MB to 512kB
as we assume that our small watches need less memory than merrifield phones.
This optimization should save around 15MB of RAM on our kernel.

Change-Id: Ic6737eb41b4286707193e6487287aa9cc2c57d26
Tracked-On: https://jira01.devtools.intel.com/browse/AW-4180


Signed-off-by: Simon Dubray <simonx.dubray@intel.com>
Reviewed-on: https://android.intel.com/564929


Reviewed-by: jenkins_ndg <jenkins_ndg@intel.com>
Reviewed-by: Deverge, Jean-francoisX <jean-francoisx.deverge@intel.com>
Reviewed-by: Gong, Sophia <sophia.gong@intel.com>
Reviewed-by: Whitfield, MichaelX <michaelx.whitfield@intel.com>
Reviewed-by: Ben Alaya, AymenX <aymenx.ben.alaya@intel.com>
Reviewed-by: Louis, FabienX <fabienx.louis@intel.com>
Reviewed-by: Tasayco Loarte, VictorX <victorx.tasayco.loarte@intel.com>
Reviewed-by: Ledentec, AlexandreX <alexandrex.ledentec@intel.com>
Reviewed-by: Korpershoek, MattijsX <mattijsx.korpershoek@intel.com>

drivers/external_drivers/intel_media/common/psb_gtt.c

@@ -385,7 +385,7 @@ int psb_gtt_mm_init(struct psb_gtt *pg)
 	spin_lock_init(&gtt_mm->lock);
 
 	ht = &gtt_mm->hash;
-	ret = drm_ht_create(ht, 20);
+	ret = drm_ht_create(ht, 16);
 	if (ret) {
 		DRM_DEBUG("Create hash table failed(%d)\n", ret);
 		goto err_free;
@@ -513,7 +513,7 @@ static int psb_gtt_mm_alloc_insert_ht(struct psb_gtt_mm *mm,
 		return -ENOMEM;
 	}
 
-	ret = drm_ht_create(&hentry->ht, 20);
+	ret = drm_ht_create(&hentry->ht, 16);
 	if (ret) {
 		DRM_DEBUG("Create hash table failed\n");
 		goto failed_drm_ht_create;

drivers/external_drivers/intel_media/display/tng/drv/psb_gtt.c

@@ -537,7 +537,7 @@ int psb_gtt_mm_init(struct psb_gtt *pg)
 	spin_lock_init(&gtt_mm->lock);
 
 	ht = &gtt_mm->hash;
-	ret = drm_ht_create(ht, 20);
+	ret = drm_ht_create(ht, 16);
 	if (ret) {
 		DRM_DEBUG("Create hash table failed(%d)\n", ret);
 		goto err_free;
@@ -669,7 +669,7 @@ static int psb_gtt_mm_alloc_insert_ht(struct psb_gtt_mm *mm,
 		return -ENOMEM;
 	}
 
-	ret = drm_ht_create(&hentry->ht, 20);
+	ret = drm_ht_create(&hentry->ht, 16);
 	if (ret) {
 		DRM_DEBUG("Create hash table failed\n");
 		return ret;