我是 Ubuntu 新手。我已经为 pptp 连接配置了 VPN。但收到以下错误：
3 23:18:32 rana-laptop kernel: [ 933.399299] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:18:32 rana-laptop kernel: [ 933.399304] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:18:51 rana-laptop blueman-mechanism: Exiting
Jul 3 23:19:24 rana-laptop kernel: [ 985.105165] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:19:24 rana-laptop kernel: [ 985.107417] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:19:24 rana-laptop kernel: [ 985.107432] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:20:16 rana-laptop kernel: [ 1036.816962] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:20:16 rana-laptop kernel: [ 1036.819187] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:20:16 rana-laptop kernel: [ 1036.819192] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:20:39 rana-laptop wpa_supplicant[1173]: message repeated 4 times: [ wlan0: CTRL-EVENT-SCAN-STARTED ]
Jul 3 23:20:55 rana-laptop wpa_supplicant[1173]: wlan0: WPA: Group rekeying completed with ba:b4:2e:4a:4f:f3 [GTK=CCMP]
Jul 3 23:21:07 rana-laptop kernel: [ 1088.528858] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:21:07 rana-laptop kernel: [ 1088.531105] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:21:07 rana-laptop kernel: [ 1088.531114] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:21:59 rana-laptop kernel: [ 1140.240949] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:21:59 rana-laptop kernel: [ 1140.243192] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:21:59 rana-laptop kernel: [ 1140.243197] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:22:39 rana-laptop wpa_supplicant[1173]: wlan0: CTRL-EVENT-SCAN-STARTED
Jul 3 23:22:51 rana-laptop kernel: [ 1191.953058] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:22:51 rana-laptop kernel: [ 1191.955292] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:22:51 rana-laptop kernel: [ 1191.955297] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:23:43 rana-laptop kernel: [ 1243.669071] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:23:43 rana-laptop kernel: [ 1243.671335] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:23:43 rana-laptop kernel: [ 1243.671342] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:24:34 rana-laptop kernel: [ 1295.380890] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:24:34 rana-laptop kernel: [ 1295.383138] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:24:34 rana-laptop kernel: [ 1295.383142] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:25:26 rana-laptop kernel: [ 1347.093112] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:25:26 rana-laptop kernel: [ 1347.095490] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:25:26 rana-laptop kernel: [ 1347.095494] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:26:18 rana-laptop kernel: [ 1398.804906] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:26:18 rana-laptop kernel: [ 1398.807133] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:26:18 rana-laptop kernel: [ 1398.807137] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:27:09 rana-laptop kernel: [ 1450.516937] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:27:09 rana-laptop kernel: [ 1450.519182] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:27:09 rana-laptop kernel: [ 1450.519185] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:28:01 rana-laptop kernel: [ 1502.228943] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:28:01 rana-laptop kernel: [ 1502.231179] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:28:01 rana-laptop kernel: [ 1502.231183] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:28:53 rana-laptop kernel: [ 1553.940850] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:28:53 rana-laptop kernel: [ 1553.943209] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:28:53 rana-laptop kernel: [ 1553.943213] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:29:44 rana-laptop kernel: [ 1605.653111] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:29:44 rana-laptop kernel: [ 1605.655362] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:29:44 rana-laptop kernel: [ 1605.655367] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:30:36 rana-laptop kernel: [ 1657.365019] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:30:36 rana-laptop kernel: [ 1657.367256] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:30:36 rana-laptop kernel: [ 1657.367260] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:30:39 rana-laptop wpa_supplicant[1173]: message repeated 4 times: [ wlan0: CTRL-EVENT-SCAN-STARTED ]
Jul 3 23:30:55 rana-laptop wpa_supplicant[1173]: wlan0: WPA: Group rekeying completed with ba:b4:2e:4a:4f:f3 [GTK=CCMP]
Jul 3 23:31:28 rana-laptop kernel: [ 1709.076983] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:31:28 rana-laptop kernel: [ 1709.079225] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:31:28 rana-laptop kernel: [ 1709.079229] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:32:20 rana-laptop kernel: [ 1760.788862] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:32:20 rana-laptop kernel: [ 1760.791107] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:32:20 rana-laptop kernel: [ 1760.791111] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:32:39 rana-laptop wpa_supplicant[1173]: wlan0: CTRL-EVENT-SCAN-STARTED
Jul 3 23:33:11 rana-laptop kernel: [ 1812.500948] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:33:11 rana-laptop kernel: [ 1812.503305] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:33:11 rana-laptop kernel: [ 1812.503309] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:34:03 rana-laptop kernel: [ 1864.209031] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:34:03 rana-laptop kernel: [ 1864.211405] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:34:03 rana-laptop kernel: [ 1864.211410] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:34:55 rana-laptop kernel: [ 1915.924935] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:34:55 rana-laptop kernel: [ 1915.927169] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:34:55 rana-laptop kernel: [ 1915.927173] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:35:31 rana-laptop compiz: pam_ecryptfs: seteuid error
Jul 3 23:35:46 rana-laptop kernel: [ 1967.636913] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:35:46 rana-laptop kernel: [ 1967.639154] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:35:46 rana-laptop kernel: [ 1967.639159] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:36:38 rana-laptop kernel: [ 2019.349008] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:36:38 rana-laptop kernel: [ 2019.351254] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:36:38 rana-laptop kernel: [ 2019.351258] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:37:30 rana-laptop kernel: [ 2071.061029] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:37:30 rana-laptop kernel: [ 2071.063277] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:37:30 rana-laptop kernel: [ 2071.063281] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:37:53 rana-laptop dbus[446]: [system] Activating service name='org.freedesktop.hostname1' (using servicehelper)
Jul 3 23:37:54 rana-laptop dbus[446]: [system] Successfully activated service 'org.freedesktop.hostname1'
Jul 3 23:38:18 rana-laptop kernel: [ 2119.278590] usb 2-3: USB disconnect, device number 3
Jul 3 23:38:19 rana-laptop kernel: [ 2119.803552] sd 7:0:0:0: [sdc] Synchronizing SCSI cache
Jul 3 23:38:19 rana-laptop kernel: [ 2119.803598] sd 7:0:0:0: [sdc]
Jul 3 23:38:19 rana-laptop kernel: [ 2119.803602] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK
Jul 3 23:38:19 rana-laptop udisksd[3197]: Cleaning up mount point /media/rana/Transcend (device 8:33 no longer exist)
Jul 3 23:38:22 rana-laptop kernel: [ 2122.769094] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:38:22 rana-laptop kernel: [ 2122.771338] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:38:22 rana-laptop kernel: [ 2122.771342] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:38:39 rana-laptop colord: Automatic metadata add icc-d2c4368212b5b7a9b0e167aa7ceebc74 to xrandr-Goldstar Company Ltd-E1942-303INRC5R542
Jul 3 23:38:39 rana-laptop colord: Device added: xrandr-Goldstar Company Ltd-E1942-303INRC5R542
Jul 3 23:39:01 rana-laptop CRON[11253]: (root) CMD ( [ -x /usr/lib/php5/maxlifetime ] && [ -x /usr/lib/php5/sessionclean ] && [ -d /var/lib/php5 ] && /usr/lib/php5/sessionclean /var/lib/php5 $(/usr/lib/php5/maxlifetime))
Jul 3 23:39:13 rana-laptop kernel: [ 2174.484964] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:39:13 rana-laptop kernel: [ 2174.487206] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:39:13 rana-laptop kernel: [ 2174.487210] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:40:05 rana-laptop kernel: [ 2226.196949] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:40:05 rana-laptop kernel: [ 2226.199315] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:40:05 rana-laptop kernel: [ 2226.199319] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:40:39 rana-laptop wpa_supplicant[1173]: message repeated 4 times: [ wlan0: CTRL-EVENT-SCAN-STARTED ]
Jul 3 23:40:55 rana-laptop wpa_supplicant[1173]: wlan0: WPA: Group rekeying completed with ba:b4:2e:4a:4f:f3 [GTK=CCMP]
Jul 3 23:40:57 rana-laptop kernel: [ 2277.909123] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:40:57 rana-laptop kernel: [ 2277.911354] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:40:57 rana-laptop kernel: [ 2277.911358] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:41:48 rana-laptop kernel: [ 2329.621184] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:41:48 rana-laptop kernel: [ 2329.623427] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:41:48 rana-laptop kernel: [ 2329.623432] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:42:34 rana-laptop kernel: [ 2375.169420] perf samples too long (5001 > 5000), lowering kernel.perf_event_max_sample_rate to 25000
Jul 3 23:42:39 rana-laptop wpa_supplicant[1173]: wlan0: CTRL-EVENT-SCAN-STARTED
Jul 3 23:42:40 rana-laptop kernel: [ 2381.333071] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:42:40 rana-laptop kernel: [ 2381.335317] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:42:40 rana-laptop kernel: [ 2381.335321] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:43:32 rana-laptop kernel: [ 2433.044993] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:43:32 rana-laptop kernel: [ 2433.047237] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:43:32 rana-laptop kernel: [ 2433.047243] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:44:24 rana-laptop kernel: [ 2484.756958] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:44:24 rana-laptop kernel: [ 2484.759329] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:44:24 rana-laptop kernel: [ 2484.759333] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:44:32 rana-laptop udisksd[3197]: Mounted /dev/sr0 at /media/rana/RESOURCE_CD on behalf of uid 1000
Jul 3 23:44:34 rana-laptop dbus[446]: [system] Activating service name='org.freedesktop.hostname1' (using servicehelper)
Jul 3 23:44:34 rana-laptop dbus[446]: [system] Successfully activated service 'org.freedesktop.hostname1'
Jul 3 23:44:47 rana-laptop udisksd[3197]: Cleaning up mount point /media/rana/RESOURCE_CD (device 11:0 is not mounted)
Jul 3 23:44:47 rana-laptop udisksd[3197]: Unmounted /dev/sr0 on behalf of uid 1000
Jul 3 23:45:15 rana-laptop kernel: [ 2536.469075] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:45:15 rana-laptop kernel: [ 2536.471322] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:45:15 rana-laptop kernel: [ 2536.471326] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:46:07 rana-laptop kernel: [ 2588.181213] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:46:07 rana-laptop kernel: [ 2588.183453] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:46:07 rana-laptop kernel: [ 2588.183457] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:46:59 rana-laptop kernel: [ 2639.889076] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:46:59 rana-laptop kernel: [ 2639.891454] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:46:59 rana-laptop kernel: [ 2639.891460] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:47:50 rana-laptop kernel: [ 2691.601126] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:47:50 rana-laptop kernel: [ 2691.603652] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:47:50 rana-laptop kernel: [ 2691.603659] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:48:42 rana-laptop kernel: [ 2743.317140] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:48:42 rana-laptop kernel: [ 2743.319380] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:48:42 rana-laptop kernel: [ 2743.319385] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:49:34 rana-laptop kernel: [ 2795.025249] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:49:34 rana-laptop kernel: [ 2795.027507] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:49:34 rana-laptop kernel: [ 2795.027515] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:50:26 rana-laptop kernel: [ 2846.741064] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:50:26 rana-laptop kernel: [ 2846.743306] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:50:26 rana-laptop kernel: [ 2846.743310] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:50:39 rana-laptop wpa_supplicant[1173]: message repeated 4 times: [ wlan0: CTRL-EVENT-SCAN-STARTED ]
Jul 3 23:50:55 rana-laptop wpa_supplicant[1173]: wlan0: WPA: Group rekeying completed with ba:b4:2e:4a:4f:f3 [GTK=CCMP]
Jul 3 23:51:17 rana-laptop kernel: [ 2898.452989] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:51:17 rana-laptop kernel: [ 2898.455231] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:51:17 rana-laptop kernel: [ 2898.455235] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:52:09 rana-laptop kernel: [ 2950.164860] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:52:09 rana-laptop kernel: [ 2950.167271] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:52:09 rana-laptop kernel: [ 2950.167282] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:52:39 rana-laptop wpa_supplicant[1173]: wlan0: CTRL-EVENT-SCAN-STARTED
Jul 3 23:53:01 rana-laptop kernel: [ 3001.877213] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:53:01 rana-laptop kernel: [ 3001.879461] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:53:01 rana-laptop kernel: [ 3001.879467] sd 0:0:0:0: [sda] Assuming drive cache: write through
Jul 3 23:53:52 rana-laptop kernel: [ 3053.589056] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
Jul 3 23:53:52 rana-laptop kernel: [ 3053.591298] sd 0:0:0:0: [sda] Asking for cache data failed
Jul 3 23:53:52 rana-laptop kernel: [ 3053.591302] sd 0:0:0:0: [sda] Assuming drive cache: write through
请帮忙。