From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Date: Thu, 09 Jan 2014 08:27:27 +0000 Subject: Re: [PATCH 1/2] ARM: omapfb: add coherent dma memory support Message-Id: <52CE5D6F.3050700@ti.com> MIME-Version: 1 Content-Type: multipart/mixed; boundary="VPQAPc17Q8mJBxtiS6N4leCEnUxGgOv1q" List-Id: References: <1388409550-10720-1-git-send-email-tomi.valkeinen@ti.com> <1388409550-10720-2-git-send-email-tomi.valkeinen@ti.com> <20140107235951.GH5074@atomide.com> <52CD5D13.9090806@ti.com> <79CD15C6BA57404B839C016229A409A83EDB11F5@DBDE04.ent.ti.com> <52CE5123.9050702@gmail.com> <79CD15C6BA57404B839C016229A409A83EDB141E@DBDE04.ent.ti.com> In-Reply-To: <79CD15C6BA57404B839C016229A409A83EDB141E@DBDE04.ent.ti.com> To: linux-arm-kernel@lists.infradead.org --VPQAPc17Q8mJBxtiS6N4leCEnUxGgOv1q Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 2014-01-09 10:08, Hiremath, Vaibhav wrote: > No, that's what is causing issue to me. Can you try predefined address = flow? > Just to highlight, I get UNDERFLOW during boot itself, immediately when= it gets mapped to userspace. >=20 > Boot LOG: >=20 > [ 4.822549] Freeing unused kernel memory: 440K (c0919000 - c0987000)= > [ 5.276615] OMAPFB: pan_display(0) > [ 5.276625] OMAPFB: setcmap > [ 5.276635] OMAPFB: setcmap > [ 5.293518] OMAPFB: user mmap region start a0000000, len 1536000, of= f 0 > [ 5.300171] omapdss APPLY error: FIFO UNDERFLOW on gfx, disabling th= e overlay Hmm that's interesting... So you have some tool that's ran early, which draws something on the screen? Or maybe that's X starting? Ah... I think I understand now. As I mentioned, AM4x has issues already. I think the CPU/others can block DSS when accessing memory. So, if we have bad caching for the mapped framebuffer, the CPU will use more bandwidth when reading/writing to it, and that will cause DSS to underflo= w. Tomi --VPQAPc17Q8mJBxtiS6N4leCEnUxGgOv1q Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJSzl1vAAoJEPo9qoy8lh710+YP/iz+A2RU6jrKV1LlNkvAe//u pEZj7C183Gk1j6btYHi5SFQuE7PlTQ2nE6rMFxVerU/nIpWJS3VSBr/yAOspMlQG jtO4oPGHgZnD5kGksNhRahD1W3H88fk1oe3IWEGViFXrxfP9DBIXft45UEQNwiFP zFRWRDdYdzLezQrPL4afqBzkypBJ/wsy8heJkmI3Xc6ExY3Htrgp8fR8lsPdVXw6 nacP6ooRrKF7Kj2IceztnJPaDY66ARiyK3GyJ1TaBZjJgXc9MhYOZ11hYXjQcizQ 1uACHKduSoJCDAnFDQZQq6ONhSBC8Naxmh7owZFkk2MIn2c65dtvxAKHuSuHxmdz 6QLE1+GKLCSkuWOgnRQn2OV6A4l3Gyp08aGhTJPRz0pK/GYNzrgEFD/9qZ5QPLkb 8YBI99EDeQgZL1XpaJi/ZYYSb+hd2NzWCT3YeSD4tKZIGF6ffPz/XiSUmcd3ql9j PnlOnZ/pXe+OWc8Uxd/IgabrzE0RP/m8MoBkUvOHJX7owVOsHI84jiWW8u33ZvFg DcrGBG5kqLDvBcbMyonbCP1OO2AwcBHD35fmPhHaJSa+RhevFvJaH/ZVAawtHXbU NALcACcjqGewT1j1SxarxIQhqsJXAixsQ8E82O1wzx/GnaNM9wJhibffBWw8LVIo QBp4xUEAGacFuc2H2c/O =1I2p -----END PGP SIGNATURE----- --VPQAPc17Q8mJBxtiS6N4leCEnUxGgOv1q--