diff --git a/bin/pt-mysql-summary b/bin/pt-mysql-summary
index 00603324..854b8724 100755
--- a/bin/pt-mysql-summary
+++ b/bin/pt-mysql-summary
@@ -1783,8 +1783,15 @@ section_percona_server_features () {
    name_val "Response Time Hist."   \
             "$(feat_on_renamed "$file" "enable_query_response_time_stats,query_response_time_stats")"
 
-   name_val "Smooth Flushing"       \
-            "$(feat_on_renamed "$file" "innodb_adaptive_checkpoint,innodb_adaptive_flushing_method")"
+   local smooth_flushing="$(feat_on_renamed "$file" "innodb_adaptive_checkpoint,innodb_adaptive_flushing_method")"
+   if  [ "${smooth_flushing:-""}" != "Not Supported" ]; then
+      if [ -n "$(get_var innodb_adaptive_checkpoint "$file")" ]; then
+         smooth_flushing="$(feat_on "$file" "innodb_adaptive_checkpoint" ne none)"
+      else
+         smooth_flushing="$(feat_on "$file" "innodb_adaptive_flushing_method" ne native)"
+      fi
+   fi
+   name_val "Smooth Flushing" "$smooth_flushing"
    
    name_val "HandlerSocket NoSQL"   \
             "$(feat_on "$file" handlersocket_port)"
diff --git a/lib/bash/report_mysql_info.sh b/lib/bash/report_mysql_info.sh
index 8c45ea6d..af604360 100644
--- a/lib/bash/report_mysql_info.sh
+++ b/lib/bash/report_mysql_info.sh
@@ -878,8 +878,17 @@ section_percona_server_features () {
             "$(feat_on_renamed "$file" "enable_query_response_time_stats,query_response_time_stats")"
 
    # Renamed to innodb_adaptive_flushing_method in 5.5
-   name_val "Smooth Flushing"       \
-            "$(feat_on_renamed "$file" "innodb_adaptive_checkpoint,innodb_adaptive_flushing_method")"
+   # This one is a bit more convulted than the rest because not only did it
+   # change names, but also default values: none in 5.1, native in 5.5
+   local smooth_flushing="$(feat_on_renamed "$file" "innodb_adaptive_checkpoint,innodb_adaptive_flushing_method")"
+   if  [ "${smooth_flushing:-""}" != "Not Supported" ]; then
+      if [ -n "$(get_var innodb_adaptive_checkpoint "$file")" ]; then
+         smooth_flushing="$(feat_on "$file" "innodb_adaptive_checkpoint" ne none)"
+      else
+         smooth_flushing="$(feat_on "$file" "innodb_adaptive_flushing_method" ne native)"
+      fi
+   fi
+   name_val "Smooth Flushing" "$smooth_flushing"
    
    name_val "HandlerSocket NoSQL"   \
             "$(feat_on "$file" handlersocket_port)"
diff --git a/t/lib/bash/report_mysql_info.sh b/t/lib/bash/report_mysql_info.sh
index 026443c8..4227c667 100644
--- a/t/lib/bash/report_mysql_info.sh
+++ b/t/lib/bash/report_mysql_info.sh
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-plan 34
+plan 35
 
 . "$LIB_DIR/alt_cmds.sh"
 . "$LIB_DIR/log_warn_die.sh"
@@ -741,6 +741,12 @@ no_diff \
    "$samples/expected_output_ps-features.txt" \
    "Bug 1015590: pt-mysql-summary not Percona Server 5.5-ready"
 
+section_percona_server_features "$samples/percona-server-5.1-variables" > "$PT_TMPDIR/got"
+no_diff \
+   "$PT_TMPDIR/got" \
+   "$samples/expected_output_ps-5.1-features.txt" \
+   "Bug 1015590: section_percona_server_features works on 5.1 with innodb_adaptive_checkpoint=none"
+
 # ###########################################################################
 # Done
 # ###########################################################################
diff --git a/t/pt-mysql-summary/samples/expected_output_ps-5.1-features.txt b/t/pt-mysql-summary/samples/expected_output_ps-5.1-features.txt
new file mode 100644
index 00000000..3305e641
--- /dev/null
+++ b/t/pt-mysql-summary/samples/expected_output_ps-5.1-features.txt
@@ -0,0 +1,12 @@
+      Table & Index Stats | Disabled
+     Multiple I/O Threads | Enabled
+     Corruption Resilient | Disabled
+      Durable Replication | Disabled
+     Import InnoDB Tables | Disabled
+     Fast Server Restarts | Disabled
+         Enhanced Logging | Enabled
+     Replica Perf Logging | Disabled
+      Response Time Hist. | Disabled
+          Smooth Flushing | Disabled
+      HandlerSocket NoSQL | Not Supported
+           Fast Hash UDFs | Unknown
diff --git a/t/pt-mysql-summary/samples/percona-server-5.1-variables b/t/pt-mysql-summary/samples/percona-server-5.1-variables
new file mode 100644
index 00000000..96d8312b
--- /dev/null
+++ b/t/pt-mysql-summary/samples/percona-server-5.1-variables
@@ -0,0 +1,363 @@
+auto_increment_increment	1
+auto_increment_offset	1
+autocommit	ON
+automatic_sp_privileges	ON
+back_log	50
+basedir	/home/hugmeir/mysql5/mysqlbrew/mysqls/Percona-Server-5.1/
+big_tables	OFF
+binlog_cache_size	32768
+binlog_direct_non_transactional_updates	OFF
+binlog_format	STATEMENT
+bulk_insert_buffer_size	8388608
+character_set_client	latin1
+character_set_connection	latin1
+character_set_database	latin1
+character_set_filesystem	binary
+character_set_results	latin1
+character_set_server	latin1
+character_set_system	utf8
+character_sets_dir	/home/hugmeir/mysql5/mysqlbrew/mysqls/Percona-Server-5.1/share/mysql/charsets/
+collation_connection	latin1_swedish_ci
+collation_database	latin1_swedish_ci
+collation_server	latin1_swedish_ci
+completion_type	0
+concurrent_insert	1
+connect_timeout	10
+datadir	/tmp/12345/data/
+date_format	%Y-%m-%d
+datetime_format	%Y-%m-%d %H:%i:%s
+default_week_format	0
+delay_key_write	ON
+delayed_insert_limit	100
+delayed_insert_timeout	300
+delayed_queue_size	1000
+div_precision_increment	4
+enable_query_response_time_stats	OFF
+engine_condition_pushdown	ON
+error_count	0
+event_scheduler	OFF
+expand_fast_index_creation	OFF
+expire_logs_days	0
+fast_index_creation	ON
+flush	OFF
+flush_time	0
+foreign_key_checks	ON
+ft_boolean_syntax	+ -><()~*:""&|
+ft_max_word_len	84
+ft_min_word_len	4
+ft_query_expansion_limit	20
+ft_stopword_file	(built-in)
+general_log	OFF
+general_log_file	/tmp/12345/data/mysql_sandbox12345.log
+group_concat_max_len	1024
+have_community_features	YES
+have_compress	YES
+have_crypt	YES
+have_csv	YES
+have_dynamic_loading	YES
+have_geometry	YES
+have_innodb	YES
+have_ndbcluster	NO
+have_openssl	DISABLED
+have_partitioning	YES
+have_query_cache	YES
+have_response_time_distribution	YES
+have_rtree_keys	YES
+have_ssl	DISABLED
+have_symlink	YES
+hostname	hugmeir
+identity	0
+ignore_builtin_innodb	OFF
+init_connect	
+init_file	
+init_slave	
+innodb_adaptive_checkpoint	none
+innodb_adaptive_flushing	OFF
+innodb_adaptive_hash_index	ON
+innodb_additional_mem_pool_size	8388608
+innodb_auto_lru_dump	0
+innodb_autoextend_increment	8
+innodb_autoinc_lock_mode	1
+innodb_blocking_lru_restore	OFF
+innodb_buffer_pool_shm_checksum	ON
+innodb_buffer_pool_shm_key	0
+innodb_buffer_pool_size	33554432
+innodb_change_buffering	inserts
+innodb_checkpoint_age_target	0
+innodb_checksums	ON
+innodb_commit_concurrency	0
+innodb_concurrency_tickets	500
+innodb_data_file_path	ibdata1:10M:autoextend
+innodb_data_home_dir	/tmp/12345/data
+innodb_dict_size_limit	0
+innodb_doublewrite	ON
+innodb_doublewrite_file	
+innodb_enable_unsafe_group_commit	0
+innodb_expand_import	0
+innodb_extra_rsegments	0
+innodb_extra_undoslots	OFF
+innodb_fake_changes	OFF
+innodb_fast_checksum	OFF
+innodb_fast_recovery	OFF
+innodb_fast_shutdown	1
+innodb_file_format	Antelope
+innodb_file_format_check	Antelope
+innodb_file_per_table	OFF
+innodb_flush_log_at_trx_commit	1
+innodb_flush_log_at_trx_commit_session	3
+innodb_flush_method	
+innodb_flush_neighbor_pages	1
+innodb_force_recovery	0
+innodb_ibuf_accel_rate	100
+innodb_ibuf_active_contract	1
+innodb_ibuf_max_size	16760832
+innodb_io_capacity	200
+innodb_kill_idle_transaction	0
+innodb_lazy_drop_table	0
+innodb_lock_wait_timeout	3
+innodb_locks_unsafe_for_binlog	OFF
+innodb_log_block_size	512
+innodb_log_buffer_size	8388608
+innodb_log_file_size	5242880
+innodb_log_files_in_group	2
+innodb_log_group_home_dir	/tmp/12345/data
+innodb_max_dirty_pages_pct	75
+innodb_max_purge_lag	0
+innodb_mirrored_log_groups	1
+innodb_old_blocks_pct	37
+innodb_old_blocks_time	0
+innodb_open_files	300
+innodb_overwrite_relay_log_info	OFF
+innodb_page_size	16384
+innodb_pass_corrupt_table	0
+innodb_random_read_ahead	OFF
+innodb_read_ahead	linear
+innodb_read_ahead_threshold	56
+innodb_read_io_threads	4
+innodb_recovery_stats	OFF
+innodb_replication_delay	0
+innodb_rollback_on_timeout	OFF
+innodb_show_locks_held	10
+innodb_show_verbose_locks	0
+innodb_spin_wait_delay	6
+innodb_stats_auto_update	1
+innodb_stats_method	nulls_equal
+innodb_stats_on_metadata	ON
+innodb_stats_sample_pages	8
+innodb_stats_update_need_lock	1
+innodb_strict_mode	OFF
+innodb_support_xa	ON
+innodb_sync_spin_loops	30
+innodb_table_locks	ON
+innodb_thread_concurrency	0
+innodb_thread_concurrency_timer_based	OFF
+innodb_thread_sleep_delay	10000
+innodb_use_purge_thread	1
+innodb_use_sys_malloc	ON
+innodb_use_sys_stats_table	OFF
+innodb_version	1.0.17-13.2
+innodb_write_io_threads	4
+insert_id	0
+interactive_timeout	28800
+join_buffer_size	131072
+keep_files_on_create	OFF
+key_buffer_size	16777216
+key_cache_age_threshold	300
+key_cache_block_size	1024
+key_cache_division_limit	100
+language	/home/hugmeir/mysql5/mysqlbrew/mysqls/Percona-Server-5.1/share/mysql/english/
+large_files_support	ON
+large_page_size	0
+large_pages	OFF
+last_insert_id	0
+lc_time_names	en_US
+license	GPL
+local_infile	ON
+locked_in_memory	OFF
+log	OFF
+log_bin	ON
+log_bin_trust_function_creators	OFF
+log_bin_trust_routine_creators	OFF
+log_error	/tmp/12345/data/mysqld.log
+log_output	FILE
+log_queries_not_using_indexes	OFF
+log_slave_updates	ON
+log_slow_admin_statements	OFF
+log_slow_filter	
+log_slow_queries	OFF
+log_slow_rate_limit	1
+log_slow_slave_statements	OFF
+log_slow_sp_statements	ON
+log_slow_timestamp_every	OFF
+log_slow_verbosity	full
+log_warnings	1
+long_query_time	10.000000
+low_priority_updates	OFF
+lower_case_file_system	OFF
+lower_case_table_names	0
+max_allowed_packet	1048576
+max_binlog_cache_size	4294963200
+max_binlog_size	1073741824
+max_connect_errors	10
+max_connections	151
+max_delayed_threads	20
+max_error_count	64
+max_heap_table_size	16777216
+max_insert_delayed_threads	20
+max_join_size	4294967295
+max_length_for_sort_data	1024
+max_long_data_size	1048576
+max_prepared_stmt_count	16382
+max_relay_log_size	0
+max_seeks_for_key	4294967295
+max_sort_length	1024
+max_sp_recursion_depth	0
+max_tmp_tables	32
+max_user_connections	0
+max_write_lock_count	4294967295
+min_examined_row_limit	0
+multi_range_count	256
+myisam_data_pointer_size	6
+myisam_max_sort_file_size	2146435072
+myisam_mmap_size	4294967295
+myisam_recover_options	OFF
+myisam_repair_threads	1
+myisam_sort_buffer_size	8388608
+myisam_stats_method	nulls_unequal
+myisam_use_mmap	OFF
+net_buffer_length	16384
+net_read_timeout	30
+net_retry_count	10
+net_write_timeout	60
+new	OFF
+old	OFF
+old_alter_table	OFF
+old_passwords	OFF
+open_files_limit	1024
+optimizer_fix	ON
+optimizer_prune_level	1
+optimizer_search_depth	62
+optimizer_switch	index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on
+pid_file	/tmp/12345/data/mysql_sandbox12345.pid
+plugin_dir	/home/hugmeir/mysql5/mysqlbrew/mysqls/Percona-Server-5.1/lib/mysql/plugin
+port	12345
+preload_buffer_size	32768
+profiling	OFF
+profiling_history_size	15
+profiling_server	OFF
+profiling_use_getrusage	OFF
+protocol_version	10
+pseudo_thread_id	0
+query_alloc_block_size	8192
+query_cache_limit	1048576
+query_cache_min_res_unit	4096
+query_cache_size	0
+query_cache_strip_comments	OFF
+query_cache_type	ON
+query_cache_wlock_invalidate	OFF
+query_prealloc_size	8192
+query_response_time_range_base	10
+rand_seed1	
+rand_seed2	
+range_alloc_block_size	4096
+read_buffer_size	131072
+read_only	OFF
+read_rnd_buffer_size	262144
+relay_log	mysql-relay-bin
+relay_log_index	
+relay_log_info_file	relay-log.info
+relay_log_purge	ON
+relay_log_space_limit	0
+report_host	127.0.0.1
+report_password	
+report_port	12345
+report_user	
+rpl_recovery_rank	0
+secure_auth	OFF
+secure_file_priv	
+server_id	12345
+skip_external_locking	ON
+skip_name_resolve	OFF
+skip_networking	OFF
+skip_show_database	OFF
+slave_compressed_protocol	OFF
+slave_exec_mode	STRICT
+slave_load_tmpdir	/tmp
+slave_net_timeout	3600
+slave_skip_errors	OFF
+slave_transaction_retries	10
+slow_launch_time	2
+slow_query_log	OFF
+slow_query_log_file	/tmp/12345/data/mysql_sandbox12345-slow.log
+slow_query_log_microseconds_timestamp	OFF
+socket	/tmp/12345/mysql_sandbox12345.sock
+sort_buffer_size	2097144
+sql_auto_is_null	ON
+sql_big_selects	ON
+sql_big_tables	OFF
+sql_buffer_result	OFF
+sql_log_bin	ON
+sql_log_off	OFF
+sql_log_update	ON
+sql_low_priority_updates	OFF
+sql_max_join_size	4294967295
+sql_mode	
+sql_notes	ON
+sql_quote_show_create	ON
+sql_safe_updates	OFF
+sql_select_limit	4294967295
+sql_slave_skip_counter	
+sql_warnings	OFF
+ssl_ca	
+ssl_capath	
+ssl_cert	
+ssl_cipher	
+ssl_key	
+storage_engine	MyISAM
+suppress_log_warning_1592	OFF
+sync_binlog	0
+sync_frm	ON
+system_time_zone	ART
+table_definition_cache	256
+table_lock_wait_timeout	50
+table_open_cache	64
+table_type	MyISAM
+thread_cache_size	0
+thread_handling	one-thread-per-connection
+thread_stack	196608
+thread_statistics	OFF
+time_format	%H:%i:%s
+time_zone	SYSTEM
+timed_mutexes	OFF
+timestamp	1333157599
+tmp_table_size	16777216
+tmpdir	/tmp
+transaction_alloc_block_size	8192
+transaction_prealloc_size	4096
+tx_isolation	REPEATABLE-READ
+unique_checks	ON
+updatable_views_with_limit	YES
+use_global_log_slow_control	none
+use_global_long_query_time	OFF
+userstat_running	OFF
+version	5.1.61rel13.2-log
+version_comment	Percona Server with XtraDB (GPL), Release rel13.2, Revision 430
+version_compile_machine	i686
+version_compile_os	pc-linux-gnu
+wait_timeout	28800
+warning_count	0
+internal::nice_of_2750    0
+internal::oom_of_2750    0
+internal::nice_of_2571    0
+internal::oom_of_2571    0
+internal::nice_of_2406    0
+internal::oom_of_2406    0
+pt-summary-internal-current_time    2012-03-30 21:45
+pt-summary-internal-Config_File_path    /tmp/12345/my.sandbox.cnf
+pt-summary-internal-mysql_executable    /home/hugmeir/mysql5/mysqlbrew/mysqls/Percona-Server-5.1/bin/mysql
+pt-summary-internal-now    2012-03-30 22:33:19
+pt-summary-internal-user   msandbox@%
+pt-summary-internal-FNV_64   Unknown
+pt-summary-internal-trigger_count   6
+pt-summary-internal-mysqld_executable_1   Yes
+pt-summary-internal-pid_file_exists   1