From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Date: Mon, 01 Feb 2010 22:46:33 +0000 Subject: Re: [PATCH/RFC 2.6.33-rc5 1/1] broadsheetfb: support storing Message-Id: <20100201144633.e95da0ac.akpm@linux-foundation.org> List-Id: References: <1264395836-9892-1-git-send-email-jayakumar.lkml@gmail.com> In-Reply-To: <1264395836-9892-1-git-send-email-jayakumar.lkml@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-fbdev@vger.kernel.org On Tue, 2 Feb 2010 06:33:35 +0800 Jaya Kumar wrote: > You are right, broadsheet is a framebuffer device. It is slightly > different than a typical framebuffer controller that drives a normal > TFT-LCD display. Most E-Ink display panels require a waveform in order > to function. That is, in order to drive the state of a pixel to black, > gray, or white, a specific waveform is utilized. Basically, that > waveform represents the specific E-field wiggling needed to get the > pixel to its optimal state given current temperature, and its previous > state. TN/IPS-LCDs use a similar concept but the driving waveform is > sufficiently simple that it is internalized in the TFT source/gate > driver. > > These E-Ink waveforms are specific to a production batch. That is, a > batch of display films are produced, then they get characterized and a > waveform is generated for that batch. Broadsheet, typically, is > attached to its private SPI flash which is then flashed with this > waveform. > > Users won't be able to see the waveform and typically won't ever need > to know about it. If however, the display panel attached to broadsheet > is changed out, then they will need to update their waveform. That > would typically be done at a factory or repair facility rather than by > a user. ah, I'd never have guessed, thanks. I added that to the changelog ;)